com.unity.netcode.gameobjects@2.0.0-exp.2

The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/) and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).

Additional documentation and release notes are available at [Multiplayer Documentation](https://docs-multiplayer.unity3d.com).

## [2.0.0-exp.2] - 2024-04-02

### Added
- Added updates to all internal messages to account for a distributed authority network session connection.  (#2863)
- Added `NetworkRigidbodyBase` that provides users with a more customizable network rigidbody, handles both `Rigidbody` and `Rigidbody2D`, and provides an option to make `NetworkTransform` use the rigid body for motion.  (#2863)
  - For a customized `NetworkRigidbodyBase` class:
    - `NetworkRigidbodyBase.AutoUpdateKinematicState` provides control on whether the kinematic setting will be automatically set or not when ownership changes.
    - `NetworkRigidbodyBase.AutoSetKinematicOnDespawn` provides control on whether isKinematic will automatically be set to true when the associated `NetworkObject` is despawned.
    - `NetworkRigidbodyBase.Initialize` is a protected method that, when invoked, will initialize the instance. This includes options to:
      - Set whether using a `RigidbodyTypes.Rigidbody` or `RigidbodyTypes.Rigidbody2D`.
      - Includes additional optional parameters to set the `NetworkTransform`, `Rigidbody`, and `Rigidbody2d` to use.
  - Provides additional public methods:
    - `NetworkRigidbodyBase.GetPosition` to return the position of the `Rigidbody` or `Rigidbody2d` (depending upon its initialized setting).
    - `NetworkRigidbodyBase.GetRotation` to return the rotation of the `Rigidbody` or `Rigidbody2d` (depending upon its initialized setting).
    - `NetworkRigidbodyBase.MovePosition` to move to the position of the `Rigidbody` or `Rigidbody2d` (depending upon its initialized setting).
    - `NetworkRigidbodyBase.MoveRotation` to move to the rotation of the `Rigidbody` or `Rigidbody2d` (depending upon its initialized setting).
    - `NetworkRigidbodyBase.Move` to move to the position and rotation of the `Rigidbody` or `Rigidbody2d` (depending upon its initialized setting).
    - `NetworkRigidbodyBase.Move` to move to the position and rotation of the `Rigidbody` or `Rigidbody2d` (depending upon its initialized setting).
    - `NetworkRigidbodyBase.SetPosition` to set the position of the `Rigidbody` or `Rigidbody2d` (depending upon its initialized setting).
    - `NetworkRigidbodyBase.SetRotation` to set the rotation of the `Rigidbody` or `Rigidbody2d` (depending upon its initialized setting).
    - `NetworkRigidbodyBase.ApplyCurrentTransform` to set the position and rotation of the `Rigidbody` or `Rigidbody2d` based on the associated `GameObject` transform (depending upon its initialized setting).
    - `NetworkRigidbodyBase.WakeIfSleeping` to wake up the rigid body if sleeping.
    - `NetworkRigidbodyBase.SleepRigidbody` to put the rigid body to sleep.
    - `NetworkRigidbodyBase.IsKinematic` to determine if the `Rigidbody` or `Rigidbody2d` (depending upon its initialized setting) is currently kinematic.
    - `NetworkRigidbodyBase.SetIsKinematic` to set the `Rigidbody` or `Rigidbody2d` (depending upon its initialized setting) current kinematic state.
    - `NetworkRigidbodyBase.ResetInterpolation` to reset the `Rigidbody` or `Rigidbody2d` (depending upon its initialized setting) back to its original interpolation value when initialized.
  - Now includes a `MonoBehaviour.FixedUpdate` implementation that will update the assigned `NetworkTransform` when `NetworkRigidbodyBase.UseRigidBodyForMotion` is true. (#2863)
- Added `RigidbodyContactEventManager` that provides a more optimized way to process collision enter and collision stay events as opposed to the `Monobehaviour` approach. (#2863)
  - Can be used in client-server and distributed authority modes, but is particularly useful in distributed authority.
- Added rigid body motion updates to `NetworkTransform` which allows users to set interolation on rigid bodies. (#2863)
  - Extrapolation is only allowed on authoritative instances, but custom class derived from `NetworkRigidbodyBase` or `NetworkRigidbody` or `NetworkRigidbody2D` automatically switches non-authoritative instances to interpolation if set to extrapolation.
- Added distributed authority mode support to `NetworkAnimator`. (#2863)
- Added session mode selection to `NetworkManager` inspector view. (#2863)
- Added distributed authority permissions feature. (#2863)
- Added distributed authority mode specific `NetworkObject` permissions flags (Distributable, Transferable, and RequestRequired). (#2863)
- Added distributed authority mode specific `NetworkObject.SetOwnershipStatus` method that applies one or more `NetworkObject` instance's ownership flags. If updated when spawned, the ownership permission changes are synchronized with the other connected clients. (#2863)
- Added distributed authority mode specific `NetworkObject.RemoveOwnershipStatus` method that removes one or more `NetworkObject` instance's ownership flags. If updated when spawned, the ownership permission changes are synchronized with the other connected clients. (#2863)
- Added distributed authority mode specific `NetworkObject.HasOwnershipStatus` method that will return (true or false) whether one or more ownership flags is set. (#2863)
- Added distributed authority mode specific `NetworkObject.SetOwnershipLock` method that locks ownership of a `NetworkObject` to prevent ownership from changing until the current owner releases the lock. (#2863)
- Added distributed authority mode specific `NetworkObject.RequestOwnership` method that sends an ownership request to the current owner of a spawned `NetworkObject` instance. (#2863)
- Added distributed authority mode specific `NetworkObject.OnOwnershipRequested` callback handler that is invoked on the owner/authoritative side when a non-owner requests ownership. Depending upon the boolean returned value depends upon whether the request is approved or denied. (#2863)
- Added distributed authority mode specific `NetworkObject.OnOwnershipRequestResponse` callback handler that is invoked when a non-owner's request has been processed. This callback includes a `NetworkObjet.OwnershipRequestResponseStatus` response parameter that describes whether the request was approved or the reason why it was not approved. (#2863)
- Added distributed authority mode specific `NetworkObject.DeferDespawn` method that defers the despawning of `NetworkObject` instances on non-authoritative clients based on the tick offset parameter. (#2863)
- Added distributed authority mode specific `NetworkObject.OnDeferredDespawnComplete` callback handler that can be used to further control when deferring the despawning of a `NetworkObject` on non-authoritative instances. (#2863)
- Added `NetworkClient.SessionModeType` as one way to determine the current session mode of the network session a client is connected to. (#2863)
- Added distributed authority mode specific `NetworkClient.IsSessionOwner` property to determine if the current local client is the current session owner of a distributed authority session. (#2863)
- Added distributed authority mode specific client side spawning capabilities. When running in distributed authority mode, clients can instantiate and spawn `NetworkObject` instances (the local client is authomatically the owner of the spawned object). (#2863)
  - This is useful to better visually synchronize owner authoritative motion models and newly spawned `NetworkObject` instances (i.e. projectiles for example).
- Added distributed authority mode specific client side player spawning capabilities. Clients will automatically spawn their associated player object locally. (#2863)
- Added distributed authority mode specific `NetworkConfig.AutoSpawnPlayerPrefabClientSide` property (default is true) to provide control over the automatic spawning of player prefabs on the local client side. (#2863)
- Added distributed authority mode specific `NetworkManager.OnFetchLocalPlayerPrefabToSpawn` callback that, when assigned, will allow the local client to provide the player prefab to be spawned for the local client. (#2863)
  - This is only invoked if the `NetworkConfig.AutoSpawnPlayerPrefabClientSide` property is set to true.
- Added distributed authority mode specific `NetworkBehaviour.HasAuthority` property that determines if the local client has authority over the associated `NetworkObject` instance (typical use case is within a `NetworkBehaviour` script much like that of `IsServer` or `IsClient`). (#2863)
- Added distributed authority mode specific `NetworkBehaviour.IsSessionOwner` property that determines if the local client is the session owner (typical use case would be to determine if the local client can has scene management authority within a `NetworkBehaviour` script). (#2863)
- Added support for distributed authority mode scene management where the currently assigned session owner can start scene events (i.e. scene loading and scene unloading). (#2863)

### Fixed

- Fixed issue where the host was not invoking `OnClientDisconnectCallback` for its own local client when internally shutting down. (#2822)
- Fixed issue where NetworkTransform could potentially attempt to "unregister" a named message prior to it being registered. (#2807)
- Fixed issue where in-scene placed `NetworkObject`s with complex nested children `NetworkObject`s (more than one child in depth) would not synchronize properly if WorldPositionStays was set to true. (#2796)

### Changed
- Changed client side awareness of other clients is now the same as a server or host. (#2863)
- Changed `NetworkManager.ConnectedClients` can now be accessed by both server and clients. (#2863)
- Changed `NetworkManager.ConnectedClientsList` can now be accessed by both server and clients. (#2863)
- Changed `NetworkTransform` defaults to owner authoritative when connected to a distributed authority session. (#2863)
- Changed `NetworkVariable` defaults to owner write and everyone read permissions when connected to a distributed authority session (even if declared with server read or write permissions).  (#2863)
- Changed `NetworkObject` no longer implements the `MonoBehaviour.Update` method in order to determine whether a `NetworkObject` instance has been migrated to a different scene. Instead, only `NetworkObjects` with the `SceneMigrationSynchronization` property set will be updated internally during the `NetworkUpdateStage.PostLateUpdate` by `NetworkManager`. (#2863)
- Changed `NetworkManager` inspector view layout where properties are now organized by category. (#2863)
- Changed `NetworkTransform` to now use `NetworkTransformMessage` as opposed to named messages for NetworkTransformState updates. (#2810)
- Changed `CustomMessageManager` so it no longer attempts to register or "unregister" a null or empty string and will log an error if this condition occurs. (#2807)

CHANGELOG.md

@@ -6,6 +6,137 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 
 Additional documentation and release notes are available at [Multiplayer Documentation](https://docs-multiplayer.unity3d.com).
 
+## [2.0.0-exp.2] - 2024-04-02
+
+### Added
+- Added updates to all internal messages to account for a distributed authority network session connection.  (#2863)
+- Added `NetworkRigidbodyBase` that provides users with a more customizable network rigidbody, handles both `Rigidbody` and `Rigidbody2D`, and provides an option to make `NetworkTransform` use the rigid body for motion.  (#2863)
+  - For a customized `NetworkRigidbodyBase` class:
+    - `NetworkRigidbodyBase.AutoUpdateKinematicState` provides control on whether the kinematic setting will be automatically set or not when ownership changes.
+    - `NetworkRigidbodyBase.AutoSetKinematicOnDespawn` provides control on whether isKinematic will automatically be set to true when the associated `NetworkObject` is despawned.
+    - `NetworkRigidbodyBase.Initialize` is a protected method that, when invoked, will initialize the instance. This includes options to:
+      - Set whether using a `RigidbodyTypes.Rigidbody` or `RigidbodyTypes.Rigidbody2D`.
+      - Includes additional optional parameters to set the `NetworkTransform`, `Rigidbody`, and `Rigidbody2d` to use.
+  - Provides additional public methods:
+    - `NetworkRigidbodyBase.GetPosition` to return the position of the `Rigidbody` or `Rigidbody2d` (depending upon its initialized setting).
+    - `NetworkRigidbodyBase.GetRotation` to return the rotation of the `Rigidbody` or `Rigidbody2d` (depending upon its initialized setting).
+    - `NetworkRigidbodyBase.MovePosition` to move to the position of the `Rigidbody` or `Rigidbody2d` (depending upon its initialized setting).
+    - `NetworkRigidbodyBase.MoveRotation` to move to the rotation of the `Rigidbody` or `Rigidbody2d` (depending upon its initialized setting).
+    - `NetworkRigidbodyBase.Move` to move to the position and rotation of the `Rigidbody` or `Rigidbody2d` (depending upon its initialized setting).
+    - `NetworkRigidbodyBase.Move` to move to the position and rotation of the `Rigidbody` or `Rigidbody2d` (depending upon its initialized setting).
+    - `NetworkRigidbodyBase.SetPosition` to set the position of the `Rigidbody` or `Rigidbody2d` (depending upon its initialized setting).
+    - `NetworkRigidbodyBase.SetRotation` to set the rotation of the `Rigidbody` or `Rigidbody2d` (depending upon its initialized setting).
+    - `NetworkRigidbodyBase.ApplyCurrentTransform` to set the position and rotation of the `Rigidbody` or `Rigidbody2d` based on the associated `GameObject` transform (depending upon its initialized setting).
+    - `NetworkRigidbodyBase.WakeIfSleeping` to wake up the rigid body if sleeping.
+    - `NetworkRigidbodyBase.SleepRigidbody` to put the rigid body to sleep.
+    - `NetworkRigidbodyBase.IsKinematic` to determine if the `Rigidbody` or `Rigidbody2d` (depending upon its initialized setting) is currently kinematic.
+    - `NetworkRigidbodyBase.SetIsKinematic` to set the `Rigidbody` or `Rigidbody2d` (depending upon its initialized setting) current kinematic state.
+    - `NetworkRigidbodyBase.ResetInterpolation` to reset the `Rigidbody` or `Rigidbody2d` (depending upon its initialized setting) back to its original interpolation value when initialized.
+  - Now includes a `MonoBehaviour.FixedUpdate` implementation that will update the assigned `NetworkTransform` when `NetworkRigidbodyBase.UseRigidBodyForMotion` is true. (#2863)
+- Added `RigidbodyContactEventManager` that provides a more optimized way to process collision enter and collision stay events as opposed to the `Monobehaviour` approach. (#2863)
+  - Can be used in client-server and distributed authority modes, but is particularly useful in distributed authority.
+- Added rigid body motion updates to `NetworkTransform` which allows users to set interolation on rigid bodies. (#2863)
+  - Extrapolation is only allowed on authoritative instances, but custom class derived from `NetworkRigidbodyBase` or `NetworkRigidbody` or `NetworkRigidbody2D` automatically switches non-authoritative instances to interpolation if set to extrapolation.
+- Added distributed authority mode support to `NetworkAnimator`. (#2863)
+- Added session mode selection to `NetworkManager` inspector view. (#2863)
+- Added distributed authority permissions feature. (#2863)
+- Added distributed authority mode specific `NetworkObject` permissions flags (Distributable, Transferable, and RequestRequired). (#2863)
+- Added distributed authority mode specific `NetworkObject.SetOwnershipStatus` method that applies one or more `NetworkObject` instance's ownership flags. If updated when spawned, the ownership permission changes are synchronized with the other connected clients. (#2863)
+- Added distributed authority mode specific `NetworkObject.RemoveOwnershipStatus` method that removes one or more `NetworkObject` instance's ownership flags. If updated when spawned, the ownership permission changes are synchronized with the other connected clients. (#2863)
+- Added distributed authority mode specific `NetworkObject.HasOwnershipStatus` method that will return (true or false) whether one or more ownership flags is set. (#2863)
+- Added distributed authority mode specific `NetworkObject.SetOwnershipLock` method that locks ownership of a `NetworkObject` to prevent ownership from changing until the current owner releases the lock. (#2863)
+- Added distributed authority mode specific `NetworkObject.RequestOwnership` method that sends an ownership request to the current owner of a spawned `NetworkObject` instance. (#2863)
+- Added distributed authority mode specific `NetworkObject.OnOwnershipRequested` callback handler that is invoked on the owner/authoritative side when a non-owner requests ownership. Depending upon the boolean returned value depends upon whether the request is approved or denied. (#2863)
+- Added distributed authority mode specific `NetworkObject.OnOwnershipRequestResponse` callback handler that is invoked when a non-owner's request has been processed. This callback includes a `NetworkObjet.OwnershipRequestResponseStatus` response parameter that describes whether the request was approved or the reason why it was not approved. (#2863)
+- Added distributed authority mode specific `NetworkObject.DeferDespawn` method that defers the despawning of `NetworkObject` instances on non-authoritative clients based on the tick offset parameter. (#2863)
+- Added distributed authority mode specific `NetworkObject.OnDeferredDespawnComplete` callback handler that can be used to further control when deferring the despawning of a `NetworkObject` on non-authoritative instances. (#2863)
+- Added `NetworkClient.SessionModeType` as one way to determine the current session mode of the network session a client is connected to. (#2863)
+- Added distributed authority mode specific `NetworkClient.IsSessionOwner` property to determine if the current local client is the current session owner of a distributed authority session. (#2863)
+- Added distributed authority mode specific client side spawning capabilities. When running in distributed authority mode, clients can instantiate and spawn `NetworkObject` instances (the local client is authomatically the owner of the spawned object). (#2863)
+  - This is useful to better visually synchronize owner authoritative motion models and newly spawned `NetworkObject` instances (i.e. projectiles for example).
+- Added distributed authority mode specific client side player spawning capabilities. Clients will automatically spawn their associated player object locally. (#2863)
+- Added distributed authority mode specific `NetworkConfig.AutoSpawnPlayerPrefabClientSide` property (default is true) to provide control over the automatic spawning of player prefabs on the local client side. (#2863)
+- Added distributed authority mode specific `NetworkManager.OnFetchLocalPlayerPrefabToSpawn` callback that, when assigned, will allow the local client to provide the player prefab to be spawned for the local client. (#2863)
+  - This is only invoked if the `NetworkConfig.AutoSpawnPlayerPrefabClientSide` property is set to true.
+- Added distributed authority mode specific `NetworkBehaviour.HasAuthority` property that determines if the local client has authority over the associated `NetworkObject` instance (typical use case is within a `NetworkBehaviour` script much like that of `IsServer` or `IsClient`). (#2863)
+- Added distributed authority mode specific `NetworkBehaviour.IsSessionOwner` property that determines if the local client is the session owner (typical use case would be to determine if the local client can has scene management authority within a `NetworkBehaviour` script). (#2863)
+- Added support for distributed authority mode scene management where the currently assigned session owner can start scene events (i.e. scene loading and scene unloading). (#2863)
+
+### Fixed
+
+- Fixed issue where the host was not invoking `OnClientDisconnectCallback` for its own local client when internally shutting down. (#2822)
+- Fixed issue where NetworkTransform could potentially attempt to "unregister" a named message prior to it being registered. (#2807)
+- Fixed issue where in-scene placed `NetworkObject`s with complex nested children `NetworkObject`s (more than one child in depth) would not synchronize properly if WorldPositionStays was set to true. (#2796)
+
+### Changed
+- Changed client side awareness of other clients is now the same as a server or host. (#2863)
+- Changed `NetworkManager.ConnectedClients` can now be accessed by both server and clients. (#2863)
+- Changed `NetworkManager.ConnectedClientsList` can now be accessed by both server and clients. (#2863)
+- Changed `NetworkTransform` defaults to owner authoritative when connected to a distributed authority session. (#2863)
+- Changed `NetworkVariable` defaults to owner write and everyone read permissions when connected to a distributed authority session (even if declared with server read or write permissions).  (#2863)
+- Changed `NetworkObject` no longer implements the `MonoBehaviour.Update` method in order to determine whether a `NetworkObject` instance has been migrated to a different scene. Instead, only `NetworkObjects` with the `SceneMigrationSynchronization` property set will be updated internally during the `NetworkUpdateStage.PostLateUpdate` by `NetworkManager`. (#2863)
+- Changed `NetworkManager` inspector view layout where properties are now organized by category. (#2863)
+- Changed `NetworkTransform` to now use `NetworkTransformMessage` as opposed to named messages for NetworkTransformState updates. (#2810)
+- Changed `CustomMessageManager` so it no longer attempts to register or "unregister" a null or empty string and will log an error if this condition occurs. (#2807)
+
+## [1.8.1] - 2024-02-05
+
+### Fixed
+
+- Fixed a compile error when compiling for IL2CPP targets when using the new `[Rpc]` attribute. (#2824)
+
+## [1.8.0] - 2023-12-12
+
+### Added
+
+- Added a new RPC attribute, which is simply `Rpc`. (#2762)
+  - This is a generic attribute that can perform the functions of both Server and Client RPCs, as well as enabling client-to-client RPCs. Includes several default targets: `Server`, `NotServer`, `Owner`, `NotOwner`, `Me`, `NotMe`, `ClientsAndHost`, and `Everyone`. Runtime overrides are available for any of these targets, as well as for sending to a specific ID or groups of IDs.
+  - This attribute also includes the ability to defer RPCs that are sent to the local process to the start of the next frame instead of executing them immediately, treating them as if they had gone across the network. The default behavior is to execute immediately.
+  - This attribute effectively replaces `ServerRpc` and `ClientRpc`. `ServerRpc` and `ClientRpc` remain in their existing forms for backward compatibility, but `Rpc` will be the recommended and most supported option.
+- Added `NetworkManager.OnConnectionEvent` as a unified connection event callback to notify clients and servers of all client connections and disconnections within the session (#2762)
+- Added `NetworkManager.ServerIsHost` and `NetworkBehaviour.ServerIsHost` to allow a client to tell if it is connected to a host or to a dedicated server (#2762)
+- Added `SceneEventProgress.SceneManagementNotEnabled` return status to be returned when a `NetworkSceneManager` method is invoked and scene management is not enabled. (#2735)
+- Added `SceneEventProgress.ServerOnlyAction` return status to be returned when a `NetworkSceneManager` method is invoked by a client. (#2735)
+- Added `NetworkObject.InstantiateAndSpawn` and `NetworkSpawnManager.InstantiateAndSpawn` methods to simplify prefab spawning by assuring that the prefab is valid and applies any override prior to instantiating the `GameObject` and spawning the `NetworkObject` instance. (#2710)
+
+### Fixed
+
+- Fixed issue where a client disconnected by a server-host would not receive a local notification. (#2789)
+- Fixed issue where a server-host could shutdown during a relay connection but periodically the transport disconnect message sent to any connected clients could be dropped. (#2789)
+- Fixed issue where a host could disconnect its local client but remain running as a server. (#2789)
+- Fixed issue where `OnClientDisconnectedCallback` was not being invoked under certain conditions. (#2789)
+- Fixed issue where `OnClientDisconnectedCallback` was always returning 0 as the client identifier. (#2789)
+- Fixed issue where if a host or server shutdown while a client owned NetworkObjects (other than the player) it would throw an exception. (#2789)
+- Fixed issue where setting values on a `NetworkVariable` or `NetworkList` within `OnNetworkDespawn` during a shutdown sequence would throw an exception. (#2789)
+- Fixed issue where a teleport state could potentially be overridden by a previous unreliable delta state. (#2777)
+- Fixed issue where `NetworkTransform` was using the `NetworkManager.ServerTime.Tick` as opposed to `NetworkManager.NetworkTickSystem.ServerTime.Tick` during the authoritative side's tick update where it performed a delta state check. (#2777)
+- Fixed issue where a parented in-scene placed NetworkObject would be destroyed upon a client or server exiting a network session but not unloading the original scene in which the NetworkObject was placed. (#2737)
+- Fixed issue where during client synchronization and scene loading, when client synchronization or the scene loading mode are set to `LoadSceneMode.Single`, a `CreateObjectMessage` could be received, processed, and the resultant spawned `NetworkObject` could be instantiated in the client's currently active scene that could, towards the end of the client synchronization or loading process, be unloaded and cause the newly created `NetworkObject` to be destroyed (and throw and exception). (#2735)
+- Fixed issue where a `NetworkTransform` instance with interpolation enabled would result in wide visual motion gaps (stuttering) under above normal latency conditions and a 1-5% or higher packet are drop rate. (#2713)
+- Fixed issue where  you could not have multiple source network prefab overrides targeting the same network prefab as their override. (#2710)
+
+### Changed
+- Changed the server or host shutdown so it will now perform a "soft shutdown" when `NetworkManager.Shutdown` is invoked. This will send a disconnect notification to all connected clients and the server-host will wait for all connected clients to disconnect or timeout after a 5 second period before completing the shutdown process. (#2789)
+- Changed `OnClientDisconnectedCallback` will now return the assigned client identifier on the local client side if the client was approved and assigned one prior to being disconnected. (#2789)
+- Changed `NetworkTransform.SetState` (and related methods) now are cumulative during a fractional tick period and sent on the next pending tick. (#2777)
+- `NetworkManager.ConnectedClientsIds` is now accessible on the client side and will contain the list of all clients in the session, including the host client if the server is operating in host mode (#2762)
+- Changed `NetworkSceneManager` to return a `SceneEventProgress` status and not throw exceptions for methods invoked when scene management is disabled and when a client attempts to access a `NetworkSceneManager` method by a client. (#2735)
+- Changed `NetworkTransform` authoritative instance tick registration so a single `NetworkTransform` specific tick event update will update all authoritative instances to improve perofmance. (#2713)
+- Changed `NetworkPrefabs.OverrideToNetworkPrefab` dictionary is no longer used/populated due to it ending up being related to a regression bug and not allowing more than one override to be assigned to a network prefab asset. (#2710)
+- Changed in-scene placed `NetworkObject`s now store their source network prefab asset's `GlobalObjectIdHash` internally that is used, when scene management is disabled, by clients to spawn the correct prefab even if the `NetworkPrefab` entry has an override. This does not impact dynamically spawning the same prefab which will yield the override on both host and client. (#2710)
+- Changed in-scene placed `NetworkObject`s no longer require a `NetworkPrefab` entry with `GlobalObjectIdHash` override in order for clients to properly synchronize. (#2710)
+- Changed in-scene placed `NetworkObject`s now set their `IsSceneObject` value when generating their `GlobalObjectIdHash` value. (#2710)
+- Changed the default `NetworkConfig.SpawnTimeout` value from 1.0s to 10.0s. (#2710)
+
+## [1.7.1] - 2023-11-15
+
+### Added
+
+### Fixed
+
+- Fixed a bug where having a class with Rpcs that inherits from a class without Rpcs that inherits from NetworkVariable would cause a compile error. (#2751)
+- Fixed issue where `NetworkBehaviour.Synchronize` was not truncating the write buffer if nothing was serialized during `NetworkBehaviour.OnSynchronize` causing an additional 6 bytes to be written per `NetworkBehaviour` component instance. (#2749)
+
 ## [1.7.0] - 2023-10-11
 
 ### Added
@@ -63,7 +194,7 @@ Additional documentation and release notes are available at [Multiplayer Documen
 ### Added
 
 ### Fixed
-
+- Bumped minimum Unity version supported to 2021.3 LTS
 - Fixed issue where `NetworkClient.OwnedObjects` was not returning any owned objects due to the `NetworkClient.IsConnected` not being properly set. (#2631)
 - Fixed a crash when calling TrySetParent with a null Transform (#2625)
 - Fixed issue where a `NetworkTransform` using full precision state updates was losing transform state updates when interpolation was enabled. (#2624)

Components/Messages.meta

@@ -0,0 +1,8 @@
+fileFormatVersion: 2
+guid: a9db1d18fa0117f4da5e8e65386b894a
+folderAsset: yes
+DefaultImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Components/Messages/NetworkTransformMessage.cs

@@ -0,0 +1,205 @@
+using Unity.Netcode.Components;
+using UnityEngine;
+
+namespace Unity.Netcode
+{
+    /// <summary>
+    /// NetworkTransform State Update Message
+    /// </summary>
+    internal struct NetworkTransformMessage : INetworkMessage
+    {
+        public int Version => 0;
+        public ulong NetworkObjectId;
+        public int NetworkBehaviourId;
+        // This is only used when serializing but not serialized
+        public bool DistributedAuthorityMode;
+        // Might get removed
+        public ulong[] TargetIds;
+
+        private int GetTargetIdLength()
+        {
+            if (TargetIds != null)
+            {
+                return TargetIds.Length;
+            }
+            return 0;
+        }
+
+        public NetworkTransform.NetworkTransformState State;
+
+        private NetworkTransform m_ReceiverNetworkTransform;
+        private FastBufferReader m_CurrentReader;
+
+        private unsafe void CopyPayload(ref FastBufferWriter writer)
+        {
+            writer.WriteBytesSafe(m_CurrentReader.GetUnsafePtrAtCurrentPosition(), m_CurrentReader.Length - m_CurrentReader.Position);
+        }
+
+        public void Serialize(FastBufferWriter writer, int targetVersion)
+        {
+            if (m_CurrentReader.IsInitialized)
+            {
+                CopyPayload(ref writer);
+            }
+            else
+            {
+                BytePacker.WriteValueBitPacked(writer, NetworkObjectId);
+                BytePacker.WriteValueBitPacked(writer, NetworkBehaviourId);
+                writer.WriteNetworkSerializable(State);
+                if (DistributedAuthorityMode)
+                {
+                    var length = GetTargetIdLength();
+                    BytePacker.WriteValuePacked(writer, length);
+                    // If no target ids, then just exit early (DAHost specific)
+                    if (length == 0)
+                    {
+                        return;
+                    }
+                    foreach (var target in TargetIds)
+                    {
+                        BytePacker.WriteValuePacked(writer, target);
+                    }
+                }
+            }
+        }
+
+        public bool Deserialize(FastBufferReader reader, ref NetworkContext context, int receivedMessageVersion)
+        {
+            var networkManager = context.SystemOwner as NetworkManager;
+            if (networkManager == null)
+            {
+                Debug.LogError($"[{nameof(NetworkTransformMessage)}] System owner context was not of type {nameof(NetworkManager)}!");
+                return false;
+            }
+            var currentPosition = reader.Position;
+            ByteUnpacker.ReadValueBitPacked(reader, out NetworkObjectId);
+            var isSpawnedLocally = networkManager.SpawnManager.SpawnedObjects.ContainsKey(NetworkObjectId);
+
+            // Only defer if the NetworkObject is not spawned yet and the local NetworkManager is not running as a DAHost.
+            if (!isSpawnedLocally && !networkManager.DAHost)
+            {
+                networkManager.DeferredMessageManager.DeferMessage(IDeferredNetworkMessageManager.TriggerType.OnSpawn, NetworkObjectId, reader, ref context);
+                return false;
+            }
+
+            // While the below check and assignment might seem out of place, this is specific to running in DAHost mode when a NetworkObject is
+            // hidden from the DAHost but is visible to other clients. Since the DAHost needs to forward updates to the clients, we ignore processing
+            // this message locally
+            var networkObject = (NetworkObject)null;
+            var isServerAuthoritative = false;
+            var ownerAuthoritativeServerSide = false;
+
+            // Get the behaviour index
+            ByteUnpacker.ReadValueBitPacked(reader, out NetworkBehaviourId);
+
+            // Deserialize the state
+            reader.ReadNetworkSerializableInPlace(ref State);
+
+            if (networkManager.DistributedAuthorityMode)
+            {
+                var targetCount = 0;
+                ByteUnpacker.ReadValueBitPacked(reader, out targetCount);
+                if (targetCount > 0)
+                {
+                    TargetIds = new ulong[targetCount];
+                }
+                var targetId = (ulong)0;
+                for (int i = 0; i < targetCount; i++)
+                {
+                    ByteUnpacker.ReadValueBitPacked(reader, out targetId);
+                    TargetIds[i] = targetId;
+                }
+            }
+
+            if (isSpawnedLocally)
+            {
+                networkObject = networkManager.SpawnManager.SpawnedObjects[NetworkObjectId];
+                // Get the target NetworkTransform
+                m_ReceiverNetworkTransform = networkObject.ChildNetworkBehaviours[NetworkBehaviourId] as NetworkTransform;
+                isServerAuthoritative = m_ReceiverNetworkTransform.IsServerAuthoritative();
+                ownerAuthoritativeServerSide = !isServerAuthoritative && networkManager.IsServer;
+            }
+            else
+            {
+                // If we are the DAHost and the NetworkObject is hidden from the host we still need to forward this message
+                ownerAuthoritativeServerSide = networkManager.DAHost && !isSpawnedLocally;
+            }
+
+            if (ownerAuthoritativeServerSide)
+            {
+                var ownerClientId = (ulong)0;
+
+                if (networkObject != null)
+                {
+                    ownerClientId = networkObject.OwnerClientId;
+                    if (ownerClientId == NetworkManager.ServerClientId)
+                    {
+                        // Ownership must have changed, ignore any additional pending messages that might have
+                        // come from a previous owner client.
+                        return true;
+                    }
+                }
+                else if (networkManager.DAHost)
+                {
+                    // Specific to distributed authority mode, the only sender of state updates will be the owner 
+                    ownerClientId = context.SenderId;
+                }
+
+                var networkDelivery = State.IsReliableStateUpdate() ? NetworkDelivery.ReliableSequenced : NetworkDelivery.UnreliableSequenced;
+
+                // Forward the state update if there are any remote clients to foward it to
+                if (networkManager.ConnectionManager.ConnectedClientsList.Count > (networkManager.IsHost ? 2 : 1))
+                {
+                    var clientCount = networkManager.DistributedAuthorityMode ? GetTargetIdLength() : networkManager.ConnectionManager.ConnectedClientsList.Count;
+                    if (clientCount == 0)
+                    {
+                        return true;
+                    }
+
+                    // This is only to copy the existing and already serialized struct for forwarding purposes only.
+                    // This will not include any changes made to this struct at this particular stage of processing the message.
+                    var currentMessage = this;
+                    // Create a new reader that replicates this message
+                    currentMessage.m_CurrentReader = new FastBufferReader(reader, Collections.Allocator.None);
+                    // Rewind the new reader to the beginning of the message's payload
+                    currentMessage.m_CurrentReader.Seek(currentPosition);
+                    // Forward the message to all connected clients that are observers of the associated NetworkObject
+
+                    for (int i = 0; i < clientCount; i++)
+                    {
+                        var clientId = networkManager.DistributedAuthorityMode ? TargetIds[i] : networkManager.ConnectionManager.ConnectedClientsList[i].ClientId;
+                        if (NetworkManager.ServerClientId == clientId || (!isServerAuthoritative && clientId == ownerClientId) ||
+                            (!networkManager.DistributedAuthorityMode && !networkObject.Observers.Contains(clientId)))
+                        {
+                            continue;
+                        }
+
+                        networkManager.MessageManager.SendMessage(ref currentMessage, networkDelivery, clientId);
+                    }
+                    // Dispose of the reader used for forwarding
+                    currentMessage.m_CurrentReader.Dispose();
+                }
+            }
+            return true;
+        }
+
+        public void Handle(ref NetworkContext context)
+        {
+            var networkManager = context.SystemOwner as NetworkManager;
+            // Only if the local NetworkManager instance is running as the DAHost we just exit if there is no local
+            // NetworkTransform component to apply the state update to (i.e. it is hidden from the DAHost and it
+            // just forwarded the state update to any other connected client)
+            if (networkManager.DAHost && m_ReceiverNetworkTransform == null)
+            {
+                return;
+            }
+
+            if (m_ReceiverNetworkTransform == null)
+            {
+                Debug.LogError($"[{nameof(NetworkTransformMessage)}][Dropped] Reciever {nameof(NetworkTransform)} was not set!");
+                return;
+            }
+            m_ReceiverNetworkTransform.TransformStateUpdate(ref State, context.SenderId);
+        }
+    }
+}

Components/Messages/NetworkTransformMessage.cs.meta

@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: dcfc8ac43fef97e42adb19b998d70c37
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Components/NetworkAnimator.cs

@@ -25,26 +25,48 @@ namespace Unity.Netcode.Components
         {
             foreach (var animationUpdate in m_SendAnimationUpdates)
             {
-                m_NetworkAnimator.SendAnimStateClientRpc(animationUpdate.AnimationMessage, animationUpdate.ClientRpcParams);
+
+                if (m_NetworkAnimator.NetworkManager.DistributedAuthorityMode)
+                {
+                    m_NetworkAnimator.SendAnimStateRpc(animationUpdate.AnimationMessage);
+                }
+                else
+                {
+                    m_NetworkAnimator.SendAnimStateClientRpc(animationUpdate.AnimationMessage, animationUpdate.ClientRpcParams);
+                }
             }
 
             m_SendAnimationUpdates.Clear();
 
             foreach (var sendEntry in m_SendParameterUpdates)
             {
-                m_NetworkAnimator.SendParametersUpdateClientRpc(sendEntry.ParametersUpdateMessage, sendEntry.ClientRpcParams);
+                if (m_NetworkAnimator.NetworkManager.DistributedAuthorityMode)
+                {
+                    m_NetworkAnimator.SendParametersUpdateRpc(sendEntry.ParametersUpdateMessage);
+                }
+                else
+                {
+                    m_NetworkAnimator.SendParametersUpdateClientRpc(sendEntry.ParametersUpdateMessage, sendEntry.ClientRpcParams);
+                }
             }
             m_SendParameterUpdates.Clear();
 
             foreach (var sendEntry in m_SendTriggerUpdates)
             {
-                if (!sendEntry.SendToServer)
+                if (m_NetworkAnimator.NetworkManager.DistributedAuthorityMode)
                 {
-                    m_NetworkAnimator.SendAnimTriggerClientRpc(sendEntry.AnimationTriggerMessage, sendEntry.ClientRpcParams);
+                    m_NetworkAnimator.SendAnimTriggerRpc(sendEntry.AnimationTriggerMessage);
                 }
                 else
                 {
-                    m_NetworkAnimator.SendAnimTriggerServerRpc(sendEntry.AnimationTriggerMessage);
+                    if (!sendEntry.SendToServer)
+                    {
+                        m_NetworkAnimator.SendAnimTriggerClientRpc(sendEntry.AnimationTriggerMessage, sendEntry.ClientRpcParams);
+                    }
+                    else
+                    {
+                        m_NetworkAnimator.SendAnimTriggerServerRpc(sendEntry.AnimationTriggerMessage);
+                    }
                 }
             }
             m_SendTriggerUpdates.Clear();
@@ -652,17 +674,14 @@ namespace Unity.Netcode.Components
                 NetworkLog.LogWarningServer($"[{gameObject.name}][{nameof(NetworkAnimator)}] {nameof(Animator)} is not assigned! Animation synchronization will not work for this instance!");
             }
 
-            if (IsServer)
+            m_ClientSendList = new List<ulong>(128);
+            m_ClientRpcParams = new ClientRpcParams
             {
-                m_ClientSendList = new List<ulong>(128);
-                m_ClientRpcParams = new ClientRpcParams
+                Send = new ClientRpcSendParams
                 {
-                    Send = new ClientRpcSendParams
-                    {
-                        TargetClientIds = m_ClientSendList
-                    }
-                };
-            }
+                    TargetClientIds = m_ClientSendList
+                }
+            };
 
             // Create a handler for state changes
             m_NetworkAnimatorStateChangeHandler = new NetworkAnimatorStateChangeHandler(this);
@@ -833,8 +852,7 @@ namespace Unity.Netcode.Components
                     stateChangeDetected = true;
                     //Debug.Log($"[Cross-Fade] To-Hash: {nt.fullPathHash} | TI-Duration: ({tt.duration}) | TI-Norm: ({tt.normalizedTime}) | From-Hash: ({m_AnimationHash[layer]}) | SI-FPHash: ({st.fullPathHash}) | SI-Norm: ({st.normalizedTime})");
                 }
-                else
-                if (!tt.anyState && tt.fullPathHash != m_TransitionHash[layer])
+                else if (!tt.anyState && tt.fullPathHash != m_TransitionHash[layer])
                 {
                     // first time in this transition for this layer
                     m_TransitionHash[layer] = tt.fullPathHash;
@@ -909,6 +927,11 @@ namespace Unity.Netcode.Components
             // Send an AnimationMessage only if there are dirty AnimationStates to send
             if (m_AnimationMessage.IsDirtyCount > 0)
             {
+                if (NetworkManager.DistributedAuthorityMode)
+                {
+                    SendAnimStateRpc(m_AnimationMessage);
+                }
+                else
                 if (!IsServer && IsOwner)
                 {
                     SendAnimStateServerRpc(m_AnimationMessage);
@@ -933,20 +956,33 @@ namespace Unity.Netcode.Components
             {
                 Parameters = m_ParameterWriter.ToArray()
             };
-
-            if (!IsServer)
+            if (NetworkManager.DistributedAuthorityMode)
             {
-                SendParametersUpdateServerRpc(parametersMessage);
-            }
-            else
-            {
-                if (sendDirect)
+                if (IsOwner)
                 {
-                    SendParametersUpdateClientRpc(parametersMessage, clientRpcParams);
+                    SendParametersUpdateRpc(parametersMessage);
                 }
                 else
                 {
-                    m_NetworkAnimatorStateChangeHandler.SendParameterUpdate(parametersMessage, clientRpcParams);
+                    Debug.LogError($"[{name}][Client-{NetworkManager.LocalClientId}] Attempting to send parameter updates but not the owner!");
+                }
+            }
+            else
+            {
+                if (!IsServer)
+                {
+                    SendParametersUpdateServerRpc(parametersMessage);
+                }
+                else
+                {
+                    if (sendDirect)
+                    {
+                        SendParametersUpdateClientRpc(parametersMessage, clientRpcParams);
+                    }
+                    else
+                    {
+                        m_NetworkAnimatorStateChangeHandler.SendParameterUpdate(parametersMessage, clientRpcParams);
+                    }
                 }
             }
         }
@@ -1053,8 +1089,7 @@ namespace Unity.Netcode.Components
                         BytePacker.WriteValuePacked(writer, valueBool);
                     }
                 }
-                else
-                if (cacheValue.Type == AnimationParamEnumWrapper.AnimatorControllerParameterFloat)
+                else if (cacheValue.Type == AnimationParamEnumWrapper.AnimatorControllerParameterFloat)
                 {
                     var valueFloat = m_Animator.GetFloat(hash);
                     fixed (void* value = cacheValue.Value)
@@ -1227,10 +1262,19 @@ namespace Unity.Netcode.Components
         }
 
         /// <summary>
-        /// Updates the client's animator's parameters
+        /// Distributed Authority: Updates the client's animator's parameters
+        /// </summary>
+        [Rpc(SendTo.NotAuthority)]
+        internal void SendParametersUpdateRpc(ParametersUpdateMessage parametersUpdate)
+        {
+            m_NetworkAnimatorStateChangeHandler.ProcessParameterUpdate(parametersUpdate);
+        }
+
+        /// <summary>
+        /// Client-Server: Updates the client's animator's parameters
         /// </summary>
         [ClientRpc]
-        internal unsafe void SendParametersUpdateClientRpc(ParametersUpdateMessage parametersUpdate, ClientRpcParams clientRpcParams = default)
+        internal void SendParametersUpdateClientRpc(ParametersUpdateMessage parametersUpdate, ClientRpcParams clientRpcParams = default)
         {
             var isServerAuthoritative = IsServerAuthoritative();
             if (!isServerAuthoritative && !IsOwner || isServerAuthoritative)
@@ -1244,7 +1288,7 @@ namespace Unity.Netcode.Components
         /// The server sets its local state and then forwards the message to the remaining clients
         /// </summary>
         [ServerRpc]
-        private unsafe void SendAnimStateServerRpc(AnimationMessage animationMessage, ServerRpcParams serverRpcParams = default)
+        private void SendAnimStateServerRpc(AnimationMessage animationMessage, ServerRpcParams serverRpcParams = default)
         {
             if (IsServerAuthoritative())
             {
@@ -1275,26 +1319,44 @@ namespace Unity.Netcode.Components
         }
 
         /// <summary>
-        /// Internally-called RPC client receiving function to update some animation state on a client
+        /// Client-Server: Internally-called RPC client-side receiving function to update animation states
         /// </summary>
         [ClientRpc]
-        internal unsafe void SendAnimStateClientRpc(AnimationMessage animationMessage, ClientRpcParams clientRpcParams = default)
+        internal void SendAnimStateClientRpc(AnimationMessage animationMessage, ClientRpcParams clientRpcParams = default)
         {
-            // This should never happen
-            if (IsHost)
+            ProcessAnimStates(animationMessage);
+        }
+
+        /// <summary>
+        /// Distributed Authority: Internally-called RPC non-authority receiving function to update animation states
+        /// </summary>
+        [Rpc(SendTo.NotAuthority)]
+        internal void SendAnimStateRpc(AnimationMessage animationMessage)
+        {
+            ProcessAnimStates(animationMessage);
+        }
+
+        private void ProcessAnimStates(AnimationMessage animationMessage)
+        {
+            if (HasAuthority)
             {
                 if (NetworkManager.LogLevel == LogLevel.Developer)
                 {
-                    NetworkLog.LogWarning("Detected the Host is sending itself animation updates! Please report this issue.");
+                    var hostOrOwner = NetworkManager.DistributedAuthorityMode ? "Owner" : "Host";
+                    var clientServerOrDAMode = NetworkManager.DistributedAuthorityMode ? "distributed authority" : "client-server";
+                    NetworkLog.LogWarning($"Detected the {hostOrOwner} is sending itself animation updates in {clientServerOrDAMode} mode! Please report this issue.");
                 }
                 return;
             }
+
             foreach (var animationState in animationMessage.AnimationStates)
             {
                 UpdateAnimationState(animationState);
             }
         }
 
+
+
         /// <summary>
         /// Server-side trigger state update request
         /// The server sets its local state and then forwards the message to the remaining clients
@@ -1339,7 +1401,18 @@ namespace Unity.Netcode.Components
         }
 
         /// <summary>
-        /// Internally-called RPC client receiving function to update a trigger when the server wants to forward
+        /// Distributed Authority: Internally-called RPC client receiving function to update a trigger when the server wants to forward
+        ///   a trigger for a client to play / reset
+        /// </summary>
+        /// <param name="animationTriggerMessage">the payload containing the trigger data to apply</param>
+        [Rpc(SendTo.NotAuthority)]
+        internal void SendAnimTriggerRpc(AnimationTriggerMessage animationTriggerMessage)
+        {
+            InternalSetTrigger(animationTriggerMessage.Hash, animationTriggerMessage.IsTriggerSet);
+        }
+
+        /// <summary>
+        /// Client Server: Internally-called RPC client receiving function to update a trigger when the server wants to forward
         ///   a trigger for a client to play / reset
         /// </summary>
         /// <param name="animationTriggerMessage">the payload containing the trigger data to apply</param>
@@ -1364,15 +1437,26 @@ namespace Unity.Netcode.Components
         /// <param name="setTrigger">sets (true) or resets (false) the trigger. The default is to set it (true).</param>
         public void SetTrigger(int hash, bool setTrigger = true)
         {
+            if (!IsSpawned)
+            {
+                NetworkLog.LogError($"[{gameObject.name}] Cannot set a synchronized trigger when the {nameof(NetworkObject)} is not spawned!");
+                return;
+            }
+
             // MTT-3564:
             // After fixing the issue with trigger controlled Transitions being synchronized twice,
             // it exposed additional issues with this logic.  Now, either the owner or the server can
             // update triggers. Since server-side RPCs are immediately invoked, for a host a trigger
             // will happen when SendAnimTriggerClientRpc is called.  For a client owner, we call the
             // SendAnimTriggerServerRpc and then trigger locally when running in owner authority mode.
-            if (IsOwner || IsServer)
+            var animTriggerMessage = new AnimationTriggerMessage() { Hash = hash, IsTriggerSet = setTrigger };
+            if (NetworkManager.DistributedAuthorityMode && HasAuthority)
+            {
+                m_NetworkAnimatorStateChangeHandler.QueueTriggerUpdateToClient(animTriggerMessage);
+                InternalSetTrigger(hash, setTrigger);
+            }
+            else if (!NetworkManager.DistributedAuthorityMode && (IsOwner || IsServer))
             {
-                var animTriggerMessage = new AnimationTriggerMessage() { Hash = hash, IsTriggerSet = setTrigger };
                 if (IsServer)
                 {
                     /// <see cref="UpdatePendingTriggerStates"/> as to why we queue

Components/NetworkDeltaPosition.cs

@@ -23,12 +23,20 @@ namespace Unity.Netcode.Components
         internal Vector3 DeltaPosition;
         internal int NetworkTick;
 
+        internal bool SynchronizeBase;
+
+        internal bool CollapsedDeltaIntoBase;
+
         /// <summary>
         /// The serialization implementation of <see cref="INetworkSerializable"/>
         /// </summary>
         public void NetworkSerialize<T>(BufferSerializer<T> serializer) where T : IReaderWriter
         {
             HalfVector3.NetworkSerialize(serializer);
+            if (SynchronizeBase)
+            {
+                serializer.SerializeValue(ref CurrentBasePosition);
+            }
         }
 
         /// <summary>
@@ -122,6 +130,7 @@ namespace Unity.Netcode.Components
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void UpdateFrom(ref Vector3 vector3, int networkTick)
         {
+            CollapsedDeltaIntoBase = false;
             NetworkTick = networkTick;
             DeltaPosition = (vector3 + PrecisionLossDelta) - CurrentBasePosition;
             for (int i = 0; i < HalfVector3.Length; i++)
@@ -136,6 +145,7 @@ namespace Unity.Netcode.Components
                         CurrentBasePosition[i] += HalfDeltaConvertedBack[i];
                         HalfDeltaConvertedBack[i] = 0.0f;
                         DeltaPosition[i] = 0.0f;
+                        CollapsedDeltaIntoBase = true;
                     }
                 }
             }
@@ -164,6 +174,8 @@ namespace Unity.Netcode.Components
             DeltaPosition = Vector3.zero;
             HalfDeltaConvertedBack = Vector3.zero;
             HalfVector3 = new HalfVector3(vector3, axisToSynchronize);
+            SynchronizeBase = false;
+            CollapsedDeltaIntoBase = false;
             UpdateFrom(ref vector3, networkTick);
         }
 

Components/NetworkRigidBodyBase.cs

@@ -0,0 +1,535 @@
+#if COM_UNITY_MODULES_PHYSICS
+using System.Runtime.CompilerServices;
+using UnityEngine;
+
+namespace Unity.Netcode.Components
+{
+    /// <summary>
+    /// NetworkRigidbodyBase is a unified <see cref="Rigidbody"/> and <see cref="Rigidbody2D"/> integration that helps to synchronize physics motion, collision, and interpolation
+    /// when used with a <see cref="NetworkTransform"/>.
+    /// </summary>
+    /// <remarks>
+    /// For a customizable netcode Rigidbody, create your own component from this class and use <see cref="Initialize(RigidbodyTypes, NetworkTransform, Rigidbody2D, Rigidbody)"/>
+    /// during instantiation (i.e. invoked from within the Awake method). You can re-initialize after having initialized but only when the <see cref="NetworkObject"/> is not spawned.
+    /// </remarks>
+    public abstract class NetworkRigidbodyBase : NetworkBehaviour
+    {
+        /// <summary>
+        /// When enabled, the associated <see cref="NetworkTransform"/> will use the Rigidbody/Rigidbody2D to apply and synchronize changes in position, rotation, and
+        /// allows for the use of Rigidbody interpolation/extrapolation.
+        /// </summary>
+        /// <remarks>
+        /// If <see cref="NetworkTransform.Interpolate"/> is enabled, non-authoritative instances can only use Rigidbody interpolation. If a network prefab is set to
+        /// extrapolation and <see cref="NetworkTransform.Interpolate"/> is enabled, then non-authoritative instances will automatically be adjusted to use Rigidbody
+        /// interpolation while the authoritative instance will still use extrapolation.
+        /// </remarks>
+        public bool UseRigidBodyForMotion;
+
+        /// <summary>
+        /// When enabled (default), automatically set the Kinematic state of the Rigidbody based on ownership.
+        /// When disabled, Kinematic state needs to be set by external script(s).
+        /// </summary>
+        public bool AutoUpdateKinematicState = true;
+
+        /// <summary>
+        /// Primarily applies to the <see cref="AutoUpdateKinematicState"/> property when disabled but you still want
+        /// the Rigidbody to be automatically set to Kinematic when despawned.
+        /// </summary>
+        public bool AutoSetKinematicOnDespawn = true;
+
+        // Determines if this is a Rigidbody or Rigidbody2D implementation
+        private bool m_IsRigidbody2D => RigidbodyType == RigidbodyTypes.Rigidbody2D;
+        // Used to cache the authority state of this Rigidbody during the last frame
+        private bool m_IsAuthority;
+        private Rigidbody m_Rigidbody;
+        private Rigidbody2D m_Rigidbody2D;
+        private NetworkTransform m_NetworkTransform;
+        private enum InterpolationTypes
+        {
+            None,
+            Interpolate,
+            Extrapolate
+        }
+        private InterpolationTypes m_OriginalInterpolation;
+
+        /// <summary>
+        /// Used to define the type of Rigidbody implemented.
+        /// <see cref=""/>
+        /// </summary>
+        public enum RigidbodyTypes
+        {
+            Rigidbody,
+            Rigidbody2D,
+        }
+
+        public RigidbodyTypes RigidbodyType { get; private set; }
+
+        /// <summary>
+        /// Initializes the networked Rigidbody based on the <see cref="RigidbodyTypes"/>
+        /// passed in as a parameter.
+        /// </summary>
+        /// <remarks>
+        /// Cannot be initialized while the associated <see cref="NetworkObject"/> is spawned.
+        /// </remarks>
+        /// <param name="rigidbodyType">type of rigid body being initialized</param>
+        /// <param name="rigidbody2D">(optional) The <see cref="Rigidbody2D"/> to be used</param>
+        /// <param name="rigidbody">(optional) The <see cref="Rigidbody"/> to be used</param>
+        protected void Initialize(RigidbodyTypes rigidbodyType, NetworkTransform networkTransform = null, Rigidbody2D rigidbody2D = null, Rigidbody rigidbody = null)
+        {
+            // Don't initialize if already spawned
+            if (IsSpawned)
+            {
+                Debug.LogError($"[{name}] Attempting to initialize while spawned is not allowed.");
+                return;
+            }
+            RigidbodyType = rigidbodyType;
+            m_Rigidbody2D = rigidbody2D;
+            m_Rigidbody = rigidbody;
+            m_NetworkTransform = networkTransform;
+
+            if (m_IsRigidbody2D && m_Rigidbody2D == null)
+            {
+                m_Rigidbody2D = GetComponent<Rigidbody2D>();
+
+            }
+            else if (m_Rigidbody == null)
+            {
+                m_Rigidbody = GetComponent<Rigidbody>();
+            }
+
+            SetOriginalInterpolation();
+
+            if (m_NetworkTransform == null)
+            {
+                m_NetworkTransform = GetComponent<NetworkTransform>();
+            }
+
+            if (m_NetworkTransform != null)
+            {
+                m_NetworkTransform.RegisterRigidbody(this);
+            }
+            else
+            {
+                throw new System.Exception($"[Missing {nameof(NetworkTransform)}] No {nameof(NetworkTransform)} is assigned or can be found during initialization!");
+            }
+
+            if (AutoUpdateKinematicState)
+            {
+                SetIsKinematic(true);
+            }
+        }
+
+        /// <summary>
+        /// Gets the position of the Rigidbody
+        /// </summary>
+        /// <returns><see cref="Vector3"/></returns>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public Vector3 GetPosition()
+        {
+            if (m_IsRigidbody2D)
+            {
+                return m_Rigidbody2D.position;
+            }
+            else
+            {
+                return m_Rigidbody.position;
+            }
+        }
+
+        /// <summary>
+        /// Gets the rotation of the Rigidbody
+        /// </summary>
+        /// <returns><see cref="Quaternion"/></returns>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public Quaternion GetRotation()
+        {
+            if (m_IsRigidbody2D)
+            {
+                var quaternion = Quaternion.identity;
+                var angles = quaternion.eulerAngles;
+                angles.z = m_Rigidbody2D.rotation;
+                quaternion.eulerAngles = angles;
+                return quaternion;
+            }
+            else
+            {
+                return m_Rigidbody.rotation;
+            }
+        }
+
+        /// <summary>
+        /// Moves the rigid body
+        /// </summary>
+        /// <param name="position">The <see cref="Vector3"/> position to move towards</param>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public void MovePosition(Vector3 position)
+        {
+            if (m_IsRigidbody2D)
+            {
+                m_Rigidbody2D.MovePosition(position);
+            }
+            else
+            {
+                m_Rigidbody.MovePosition(position);
+            }
+        }
+
+        /// <summary>
+        /// Directly applies a position (like teleporting)
+        /// </summary>
+        /// <param name="position"><see cref="Vector3"/> position to apply to the Rigidbody</param>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public void SetPosition(Vector3 position)
+        {
+            if (m_IsRigidbody2D)
+            {
+                m_Rigidbody2D.position = position;
+            }
+            else
+            {
+                m_Rigidbody.position = position;
+            }
+        }
+
+        /// <summary>
+        /// Applies the rotation and position of the <see cref="GameObject"/>'s <see cref="Transform"/>
+        /// </summary>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public void ApplyCurrentTransform()
+        {
+            if (m_IsRigidbody2D)
+            {
+                m_Rigidbody2D.position = transform.position;
+                m_Rigidbody2D.rotation = transform.eulerAngles.z;
+            }
+            else
+            {
+                m_Rigidbody.position = transform.position;
+                m_Rigidbody.rotation = transform.rotation;
+            }
+        }
+
+        /// <summary>
+        /// Rotatates the Rigidbody towards a specified rotation
+        /// </summary>
+        /// <param name="rotation">The rotation expressed as a <see cref="Quaternion"/></param>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public void MoveRotation(Quaternion rotation)
+        {
+            if (m_IsRigidbody2D)
+            {
+                m_Rigidbody2D.MoveRotation(rotation);
+            }
+            else
+            {
+                m_Rigidbody.MoveRotation(rotation);
+            }
+        }
+
+        /// <summary>
+        /// Applies a rotation to the Rigidbody
+        /// </summary>
+        /// <param name="rotation">The rotation to apply expressed as a <see cref="Quaternion"/></param>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public void SetRotation(Quaternion rotation)
+        {
+            if (m_IsRigidbody2D)
+            {
+                m_Rigidbody2D.rotation = rotation.eulerAngles.z;
+            }
+            else
+            {
+                m_Rigidbody.rotation = rotation;
+            }
+        }
+
+        /// <summary>
+        /// Sets the original interpolation of the Rigidbody while taking the Rigidbody type into consideration
+        /// </summary>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        private void SetOriginalInterpolation()
+        {
+            if (m_IsRigidbody2D)
+            {
+                switch (m_Rigidbody2D.interpolation)
+                {
+                    case RigidbodyInterpolation2D.None:
+                        {
+                            m_OriginalInterpolation = InterpolationTypes.None;
+                            break;
+                        }
+                    case RigidbodyInterpolation2D.Interpolate:
+                        {
+                            m_OriginalInterpolation = InterpolationTypes.Interpolate;
+                            break;
+                        }
+                    case RigidbodyInterpolation2D.Extrapolate:
+                        {
+                            m_OriginalInterpolation = InterpolationTypes.Extrapolate;
+                            break;
+                        }
+                }
+            }
+            else
+            {
+                switch (m_Rigidbody.interpolation)
+                {
+                    case RigidbodyInterpolation.None:
+                        {
+                            m_OriginalInterpolation = InterpolationTypes.None;
+                            break;
+                        }
+                    case RigidbodyInterpolation.Interpolate:
+                        {
+                            m_OriginalInterpolation = InterpolationTypes.Interpolate;
+                            break;
+                        }
+                    case RigidbodyInterpolation.Extrapolate:
+                        {
+                            m_OriginalInterpolation = InterpolationTypes.Extrapolate;
+                            break;
+                        }
+                }
+            }
+        }
+
+        /// <summary>
+        /// Wakes the Rigidbody if it is sleeping
+        /// </summary>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public void WakeIfSleeping()
+        {
+            if (m_IsRigidbody2D)
+            {
+                if (m_Rigidbody2D.IsSleeping())
+                {
+                    m_Rigidbody2D.WakeUp();
+                }
+            }
+            else
+            {
+                if (m_Rigidbody.IsSleeping())
+                {
+                    m_Rigidbody.WakeUp();
+                }
+            }
+        }
+
+        /// <summary>
+        /// Puts the Rigidbody to sleep
+        /// </summary>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public void SleepRigidbody()
+        {
+            if (m_IsRigidbody2D)
+            {
+                m_Rigidbody2D.Sleep();
+            }
+            else
+            {
+                m_Rigidbody.Sleep();
+            }
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public bool IsKinematic()
+        {
+            if (m_IsRigidbody2D)
+            {
+                return m_Rigidbody2D.isKinematic;
+            }
+            else
+            {
+                return m_Rigidbody.isKinematic;
+            }
+        }
+
+        /// <summary>
+        /// Sets the kinematic state of the Rigidbody and handles updating the Rigidbody's
+        /// interpolation setting based on the Kinematic state.
+        /// </summary>
+        /// <remarks>
+        /// When using the Rigidbody for <see cref="NetworkTransform"/> motion, this automatically
+        /// adjusts from extrapolation to interpolation if:
+        /// - The Rigidbody was originally set to extrapolation
+        /// - The NetworkTransform is set to interpolate
+        /// When the two above conditions are true:
+        /// - When switching from non-kinematic to kinematic this will automatically
+        /// switch the Rigidbody from extrapolation to interpolate.
+        /// - When switching from kinematic to non-kinematic this will automatically
+        /// switch the Rigidbody from interpolation back to extrapolation.
+        /// </remarks>
+        /// <param name="isKinematic"></param>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public void SetIsKinematic(bool isKinematic)
+        {
+            if (m_IsRigidbody2D)
+            {
+                m_Rigidbody2D.isKinematic = isKinematic;
+            }
+            else
+            {
+                m_Rigidbody.isKinematic = isKinematic;
+            }
+
+            // If we are not spawned, then exit early
+            if (!IsSpawned)
+            {
+                return;
+            }
+
+            if (UseRigidBodyForMotion)
+            {
+                // Only if the NetworkTransform is set to interpolate do we need to check for extrapolation
+                if (m_NetworkTransform.Interpolate && m_OriginalInterpolation == InterpolationTypes.Extrapolate)
+                {
+                    if (IsKinematic())
+                    {
+                        // If not already set to interpolate then set the Rigidbody to interpolate 
+                        if (m_Rigidbody.interpolation == RigidbodyInterpolation.Extrapolate)
+                        {
+                            // Sleep until the next fixed update when switching from extrapolation to interpolation
+                            SleepRigidbody();
+                            SetInterpolation(InterpolationTypes.Interpolate);
+                        }
+                    }
+                    else
+                    {
+                        // Switch it back to the original interpolation if non-kinematic (doesn't require sleep).
+                        SetInterpolation(m_OriginalInterpolation);
+                    }
+                }
+            }
+            else
+            {
+                SetInterpolation(m_IsAuthority ? m_OriginalInterpolation : (m_NetworkTransform.Interpolate ? InterpolationTypes.None : m_OriginalInterpolation));
+            }
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        private void SetInterpolation(InterpolationTypes interpolationType)
+        {
+            switch (interpolationType)
+            {
+                case InterpolationTypes.None:
+                    {
+                        if (m_IsRigidbody2D)
+                        {
+                            m_Rigidbody2D.interpolation = RigidbodyInterpolation2D.None;
+                        }
+                        else
+                        {
+                            m_Rigidbody.interpolation = RigidbodyInterpolation.None;
+                        }
+                        break;
+                    }
+                case InterpolationTypes.Interpolate:
+                    {
+                        if (m_IsRigidbody2D)
+                        {
+                            m_Rigidbody2D.interpolation = RigidbodyInterpolation2D.Interpolate;
+                        }
+                        else
+                        {
+                            m_Rigidbody.interpolation = RigidbodyInterpolation.Interpolate;
+                        }
+                        break;
+                    }
+                case InterpolationTypes.Extrapolate:
+                    {
+                        if (m_IsRigidbody2D)
+                        {
+                            m_Rigidbody2D.interpolation = RigidbodyInterpolation2D.Extrapolate;
+                        }
+                        else
+                        {
+                            m_Rigidbody.interpolation = RigidbodyInterpolation.Extrapolate;
+                        }
+                        break;
+                    }
+            }
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public void ResetInterpolation()
+        {
+            SetInterpolation(m_OriginalInterpolation);
+        }
+
+        protected override void OnOwnershipChanged(ulong previous, ulong current)
+        {
+            UpdateOwnershipAuthority();
+            base.OnOwnershipChanged(previous, current);
+        }
+
+        /// <summary>
+        /// Sets the authority based on whether it is server or owner authoritative
+        /// </summary>
+        /// <remarks>
+        /// Distributed authority sessions will always be owner authoritative.
+        /// </remarks>
+        internal void UpdateOwnershipAuthority()
+        {
+            if (NetworkManager.DistributedAuthorityMode)
+            {
+                // When in distributed authority mode, always use HasAuthority
+                m_IsAuthority = HasAuthority;
+            }
+            else
+            {
+                if (m_NetworkTransform.IsServerAuthoritative())
+                {
+                    m_IsAuthority = NetworkManager.IsServer;
+                }
+                else
+                {
+                    m_IsAuthority = IsOwner;
+                }
+            }
+
+            if (AutoUpdateKinematicState)
+            {
+                SetIsKinematic(!m_IsAuthority);
+            }
+        }
+
+        /// <inheritdoc />
+        public override void OnNetworkSpawn()
+        {
+            UpdateOwnershipAuthority();
+        }
+
+        /// <inheritdoc />
+        public override void OnNetworkDespawn()
+        {
+            // If we are automatically handling the kinematic state...
+            if (AutoUpdateKinematicState || AutoSetKinematicOnDespawn)
+            {
+                // Turn off physics for the rigid body until spawned, otherwise
+                // non-owners can run fixed updates before the first full
+                // NetworkTransform update and physics will be applied (i.e. gravity, etc)
+                SetIsKinematic(true);
+            }
+            SetInterpolation(m_OriginalInterpolation);
+        }
+
+        /// <summary>
+        /// When <see cref="UseRigidBodyForMotion"/> is enabled, the <see cref="NetworkTransform"/> will update Kinematic instances using
+        /// the Rigidbody's move methods allowing Rigidbody interpolation settings to be taken into consideration by the physics simulation.
+        /// </summary>
+        /// <remarks>
+        /// This will update the associated <see cref="NetworkTransform"/> during FixedUpdate which also avoids the added expense of adding
+        /// a FixedUpdate to all <see cref="NetworkTransform"/> instances where some might not be using a Rigidbody.
+        /// </remarks>
+        private void FixedUpdate()
+        {
+            if (!IsSpawned || m_NetworkTransform == null || !UseRigidBodyForMotion)
+            {
+                return;
+            }
+            m_NetworkTransform.OnFixedUpdate();
+        }
+    }
+}
+#endif // COM_UNITY_MODULES_PHYSICS
+

Components/NetworkRigidBodyBase.cs.meta

@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 8c4434f0563fb7f42b3b2993c97ae81a
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Components/NetworkRigidbody.cs

@@ -7,96 +7,14 @@ namespace Unity.Netcode.Components
     /// NetworkRigidbody allows for the use of <see cref="Rigidbody"/> on network objects. By controlling the kinematic
     /// mode of the <see cref="Rigidbody"/> and disabling it on all peers but the authoritative one.
     /// </summary>
-    [RequireComponent(typeof(Rigidbody))]
     [RequireComponent(typeof(NetworkTransform))]
+    [RequireComponent(typeof(Rigidbody))]
     [AddComponentMenu("Netcode/Network Rigidbody")]
-    public class NetworkRigidbody : NetworkBehaviour
+    public class NetworkRigidbody : NetworkRigidbodyBase
     {
-        /// <summary>
-        /// Determines if we are server (true) or owner (false) authoritative
-        /// </summary>
-        private bool m_IsServerAuthoritative;
-
-        private Rigidbody m_Rigidbody;
-        private NetworkTransform m_NetworkTransform;
-        private RigidbodyInterpolation m_OriginalInterpolation;
-
-        // Used to cache the authority state of this Rigidbody during the last frame
-        private bool m_IsAuthority;
-
-        private void Awake()
+        protected virtual void Awake()
         {
-            m_NetworkTransform = GetComponent<NetworkTransform>();
-            m_IsServerAuthoritative = m_NetworkTransform.IsServerAuthoritative();
-
-            m_Rigidbody = GetComponent<Rigidbody>();
-            m_OriginalInterpolation = m_Rigidbody.interpolation;
-
-            // Set interpolation to none if NetworkTransform is handling interpolation, otherwise it sets it to the original value
-            m_Rigidbody.interpolation = m_NetworkTransform.Interpolate ? RigidbodyInterpolation.None : m_OriginalInterpolation;
-
-            // Turn off physics for the rigid body until spawned, otherwise
-            // clients can run fixed update before the first full
-            // NetworkTransform update
-            m_Rigidbody.isKinematic = true;
-        }
-
-        /// <summary>
-        /// For owner authoritative (i.e. ClientNetworkTransform)
-        /// we adjust our authority when we gain ownership
-        /// </summary>
-        public override void OnGainedOwnership()
-        {
-            UpdateOwnershipAuthority();
-        }
-
-        /// <summary>
-        /// For owner authoritative(i.e. ClientNetworkTransform)
-        /// we adjust our authority when we have lost ownership
-        /// </summary>
-        public override void OnLostOwnership()
-        {
-            UpdateOwnershipAuthority();
-        }
-
-        /// <summary>
-        /// Sets the authority differently depending upon
-        /// whether it is server or owner authoritative
-        /// </summary>
-        private void UpdateOwnershipAuthority()
-        {
-            if (m_IsServerAuthoritative)
-            {
-                m_IsAuthority = NetworkManager.IsServer;
-            }
-            else
-            {
-                m_IsAuthority = IsOwner;
-            }
-
-            // If you have authority then you are not kinematic
-            m_Rigidbody.isKinematic = !m_IsAuthority;
-
-            // Set interpolation of the Rigidbody based on authority
-            // With authority: let local transform handle interpolation
-            // Without authority: let the NetworkTransform handle interpolation
-            m_Rigidbody.interpolation = m_IsAuthority ? m_OriginalInterpolation : RigidbodyInterpolation.None;
-        }
-
-        /// <inheritdoc />
-        public override void OnNetworkSpawn()
-        {
-            UpdateOwnershipAuthority();
-        }
-
-        /// <inheritdoc />
-        public override void OnNetworkDespawn()
-        {
-            m_Rigidbody.interpolation = m_OriginalInterpolation;
-            // Turn off physics for the rigid body until spawned, otherwise
-            // non-owners can run fixed updates before the first full
-            // NetworkTransform update and physics will be applied (i.e. gravity, etc)
-            m_Rigidbody.isKinematic = true;
+            Initialize(RigidbodyTypes.Rigidbody);
         }
     }
 }

Components/NetworkRigidbody2D.cs

@@ -7,76 +7,14 @@ namespace Unity.Netcode.Components
     /// NetworkRigidbody allows for the use of <see cref="Rigidbody2D"/> on network objects. By controlling the kinematic
     /// mode of the rigidbody and disabling it on all peers but the authoritative one.
     /// </summary>
-    [RequireComponent(typeof(Rigidbody2D))]
     [RequireComponent(typeof(NetworkTransform))]
+    [RequireComponent(typeof(Rigidbody2D))]
     [AddComponentMenu("Netcode/Network Rigidbody 2D")]
-    public class NetworkRigidbody2D : NetworkBehaviour
+    public class NetworkRigidbody2D : NetworkRigidbodyBase
     {
-        private Rigidbody2D m_Rigidbody;
-        private NetworkTransform m_NetworkTransform;
-
-        private bool m_OriginalKinematic;
-        private RigidbodyInterpolation2D m_OriginalInterpolation;
-
-        // Used to cache the authority state of this rigidbody during the last frame
-        private bool m_IsAuthority;
-
-        /// <summary>
-        /// Gets a bool value indicating whether this <see cref="NetworkRigidbody2D"/> on this peer currently holds authority.
-        /// </summary>
-        private bool HasAuthority => m_NetworkTransform.CanCommitToTransform;
-
-        private void Awake()
+        protected virtual void Awake()
         {
-            m_Rigidbody = GetComponent<Rigidbody2D>();
-            m_NetworkTransform = GetComponent<NetworkTransform>();
-        }
-
-        private void FixedUpdate()
-        {
-            if (IsSpawned)
-            {
-                if (HasAuthority != m_IsAuthority)
-                {
-                    m_IsAuthority = HasAuthority;
-                    UpdateRigidbodyKinematicMode();
-                }
-            }
-        }
-
-        // Puts the rigidbody in a kinematic non-interpolated mode on everyone but the server.
-        private void UpdateRigidbodyKinematicMode()
-        {
-            if (m_IsAuthority == false)
-            {
-                m_OriginalKinematic = m_Rigidbody.isKinematic;
-                m_Rigidbody.isKinematic = true;
-
-                m_OriginalInterpolation = m_Rigidbody.interpolation;
-                // Set interpolation to none, the NetworkTransform component interpolates the position of the object.
-                m_Rigidbody.interpolation = RigidbodyInterpolation2D.None;
-            }
-            else
-            {
-                // Resets the rigidbody back to it's non replication only state. Happens on shutdown and when authority is lost
-                m_Rigidbody.isKinematic = m_OriginalKinematic;
-                m_Rigidbody.interpolation = m_OriginalInterpolation;
-            }
-        }
-
-        /// <inheritdoc />
-        public override void OnNetworkSpawn()
-        {
-            m_IsAuthority = HasAuthority;
-            m_OriginalKinematic = m_Rigidbody.isKinematic;
-            m_OriginalInterpolation = m_Rigidbody.interpolation;
-            UpdateRigidbodyKinematicMode();
-        }
-
-        /// <inheritdoc />
-        public override void OnNetworkDespawn()
-        {
-            UpdateRigidbodyKinematicMode();
+            Initialize(RigidbodyTypes.Rigidbody2D);
         }
     }
 }

Components/RigidbodyContactEventManager.cs

@@ -0,0 +1,230 @@
+#if COM_UNITY_MODULES_PHYSICS
+using System.Collections.Generic;
+using Unity.Collections;
+using Unity.Jobs;
+using UnityEngine;
+
+namespace Unity.Netcode.Components
+{
+    public interface IContactEventHandler
+    {
+        Rigidbody GetRigidbody();
+
+        void ContactEvent(ulong eventId, Vector3 averagedCollisionNormal, Rigidbody collidingBody, Vector3 contactPoint, bool hasCollisionStay = false, Vector3 averagedCollisionStayNormal = default);
+    }
+
+    [AddComponentMenu("Netcode/Rigidbody Contact Event Manager")]
+    public class RigidbodyContactEventManager : MonoBehaviour
+    {
+        public static RigidbodyContactEventManager Instance { get; private set; }
+
+        private struct JobResultStruct
+        {
+            public bool HasCollisionStay;
+            public int ThisInstanceID;
+            public int OtherInstanceID;
+            public Vector3 AverageNormal;
+            public Vector3 AverageCollisionStayNormal;
+            public Vector3 ContactPoint;
+        }
+
+        private NativeArray<JobResultStruct> m_ResultsArray;
+        private int m_Count = 0;
+        private JobHandle m_JobHandle;
+
+        private readonly Dictionary<int, Rigidbody> m_RigidbodyMapping = new Dictionary<int, Rigidbody>();
+        private readonly Dictionary<int, IContactEventHandler> m_HandlerMapping = new Dictionary<int, IContactEventHandler>();
+
+        private void OnEnable()
+        {
+            m_ResultsArray = new NativeArray<JobResultStruct>(16, Allocator.Persistent);
+            Physics.ContactEvent += Physics_ContactEvent;
+            if (Instance != null)
+            {
+                NetworkLog.LogError($"[Invalid][Multiple Instances] Found more than one instance of {nameof(RigidbodyContactEventManager)}: {name} and {Instance.name}");
+                NetworkLog.LogError($"[Disable][Additional Instance] Disabling {name} instance!");
+                gameObject.SetActive(false);
+                return;
+            }
+            Instance = this;
+        }
+
+        public void RegisterHandler(IContactEventHandler contactEventHandler, bool register = true)
+        {
+            var rigidbody = contactEventHandler.GetRigidbody();
+            var instanceId = rigidbody.GetInstanceID();
+            if (register)
+            {
+                if (!m_RigidbodyMapping.ContainsKey(instanceId))
+                {
+                    m_RigidbodyMapping.Add(instanceId, rigidbody);
+                }
+
+                if (!m_HandlerMapping.ContainsKey(instanceId))
+                {
+                    m_HandlerMapping.Add(instanceId, contactEventHandler);
+                }
+            }
+            else
+            {
+                m_RigidbodyMapping.Remove(instanceId);
+                m_HandlerMapping.Remove(instanceId);
+            }
+        }
+
+        private void OnDisable()
+        {
+            m_JobHandle.Complete();
+            m_ResultsArray.Dispose();
+
+            Physics.ContactEvent -= Physics_ContactEvent;
+
+            m_RigidbodyMapping.Clear();
+            Instance = null;
+        }
+
+        private bool m_HasCollisions;
+        private int m_CurrentCount = 0;
+
+        private void ProcessCollisions()
+        {
+            // Process all collisions
+            for (int i = 0; i < m_Count; i++)
+            {
+                var thisInstanceID = m_ResultsArray[i].ThisInstanceID;
+                var otherInstanceID = m_ResultsArray[i].OtherInstanceID;
+                var rb0Valid = thisInstanceID != 0 && m_RigidbodyMapping.ContainsKey(thisInstanceID);
+                var rb1Valid = otherInstanceID != 0 && m_RigidbodyMapping.ContainsKey(otherInstanceID);
+                // Only notify registered rigid bodies.
+                if (!rb0Valid || !rb1Valid || !m_HandlerMapping.ContainsKey(thisInstanceID))
+                {
+                    continue;
+                }
+                if (m_ResultsArray[i].HasCollisionStay)
+                {
+                    m_HandlerMapping[thisInstanceID].ContactEvent(m_EventId, m_ResultsArray[i].AverageNormal, m_RigidbodyMapping[otherInstanceID], m_ResultsArray[i].ContactPoint, m_ResultsArray[i].HasCollisionStay, m_ResultsArray[i].AverageCollisionStayNormal);
+                }
+                else
+                {
+                    m_HandlerMapping[thisInstanceID].ContactEvent(m_EventId, m_ResultsArray[i].AverageNormal, m_RigidbodyMapping[otherInstanceID], m_ResultsArray[i].ContactPoint);
+                }
+            }
+        }
+
+        private void FixedUpdate()
+        {
+            // Only process new collisions
+            if (!m_HasCollisions && m_CurrentCount == 0)
+            {
+                return;
+            }
+
+            // This assures we won't process the same collision
+            // set after it has been processed.
+            if (m_HasCollisions)
+            {
+                m_CurrentCount = m_Count;
+                m_HasCollisions = false;
+                m_JobHandle.Complete();
+            }
+            ProcessCollisions();
+        }
+
+        private void LateUpdate()
+        {
+            m_CurrentCount = 0;
+        }
+
+        private ulong m_EventId;
+        private void Physics_ContactEvent(PhysicsScene scene, NativeArray<ContactPairHeader>.ReadOnly pairHeaders)
+        {
+            m_EventId++;
+            m_HasCollisions = true;
+            int n = pairHeaders.Length;
+            if (m_ResultsArray.Length < n)
+            {
+                m_ResultsArray.Dispose();
+                m_ResultsArray = new NativeArray<JobResultStruct>(Mathf.NextPowerOfTwo(n), Allocator.Persistent);
+            }
+            m_Count = n;
+            var job = new GetCollisionsJob()
+            {
+                PairedHeaders = pairHeaders,
+                ResultsArray = m_ResultsArray
+            };
+            m_JobHandle = job.Schedule(n, 256);
+        }
+
+        private struct GetCollisionsJob : IJobParallelFor
+        {
+            [ReadOnly]
+            public NativeArray<ContactPairHeader>.ReadOnly PairedHeaders;
+
+            public NativeArray<JobResultStruct> ResultsArray;
+
+            public void Execute(int index)
+            {
+                Vector3 averageNormal = Vector3.zero;
+                Vector3 averagePoint = Vector3.zero;
+                Vector3 averageCollisionStay = Vector3.zero;
+                int count = 0;
+                int collisionStaycount = 0;
+                int positionCount = 0;
+                for (int j = 0; j < PairedHeaders[index].pairCount; j++)
+                {
+                    ref readonly var pair = ref PairedHeaders[index].GetContactPair(j);
+
+                    if (pair.isCollisionExit)
+                    {
+                        continue;
+                    }
+
+                    for (int k = 0; k < pair.contactCount; k++)
+                    {
+                        ref readonly var contact = ref pair.GetContactPoint(k);
+                        averagePoint += contact.position;
+                        positionCount++;
+                        if (!pair.isCollisionStay)
+                        {
+                            averageNormal += contact.normal;
+                            count++;
+                        }
+                        else
+                        {
+                            averageCollisionStay += contact.normal;
+                            collisionStaycount++;
+                        }
+                    }
+                }
+
+                if (count != 0)
+                {
+                    averageNormal /= count;
+                }
+
+                if (collisionStaycount != 0)
+                {
+                    averageCollisionStay /= collisionStaycount;
+                }
+
+                if (positionCount != 0)
+                {
+                    averagePoint /= positionCount;
+                }
+
+                var result = new JobResultStruct()
+                {
+                    ThisInstanceID = PairedHeaders[index].bodyInstanceID,
+                    OtherInstanceID = PairedHeaders[index].otherBodyInstanceID,
+                    AverageNormal = averageNormal,
+                    HasCollisionStay = collisionStaycount != 0,
+                    AverageCollisionStayNormal = averageCollisionStay,
+                    ContactPoint = averagePoint
+                };
+
+                ResultsArray[index] = result;
+            }
+        }
+    }
+}
+#endif

Components/RigidbodyContactEventManager.cs.meta

@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 739e5cee846b6384988f9a47e4691836
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Documentation~/index.md

@@ -9,14 +9,14 @@ See guides below to install Unity Netcode for GameObjects, set up your project,
 - [Documentation](https://docs-multiplayer.unity3d.com/netcode/current/about)
 - [Installation](https://docs-multiplayer.unity3d.com/netcode/current/installation)
 - [First Steps](https://docs-multiplayer.unity3d.com/netcode/current/tutorials/get-started-ngo)
-- [API Reference](https://docs-multiplayer.unity3d.com/netcode/current/api/introduction)
+- [API Reference](https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@1.6/api/index.html)
 
 # Technical details
 
 ## Requirements
 
 Netcode for GameObjects targets the following Unity versions:
-- Unity 2020.3, 2021.1, 2021.2 and 2021.3
+- Unity 2021.3 (LTS), 2022.3 (LTS) and 2023.2
 
 On the following runtime platforms:
 - Windows, MacOS, and Linux

Editor/CodeGen/CodeGenHelpers.cs

@@ -21,13 +21,16 @@ namespace Unity.Netcode.Editor.CodeGen
         public const string NetcodeModuleName = "Unity.Netcode.Runtime.dll";
 
         public const string RuntimeAssemblyName = "Unity.Netcode.Runtime";
+        public const string ComponentsAssemblyName = "Unity.Netcode.Components";
 
         public static readonly string NetworkBehaviour_FullName = typeof(NetworkBehaviour).FullName;
         public static readonly string INetworkMessage_FullName = typeof(INetworkMessage).FullName;
         public static readonly string ServerRpcAttribute_FullName = typeof(ServerRpcAttribute).FullName;
         public static readonly string ClientRpcAttribute_FullName = typeof(ClientRpcAttribute).FullName;
+        public static readonly string RpcAttribute_FullName = typeof(RpcAttribute).FullName;
         public static readonly string ServerRpcParams_FullName = typeof(ServerRpcParams).FullName;
         public static readonly string ClientRpcParams_FullName = typeof(ClientRpcParams).FullName;
+        public static readonly string RpcParams_FullName = typeof(RpcParams).FullName;
         public static readonly string ClientRpcSendParams_FullName = typeof(ClientRpcSendParams).FullName;
         public static readonly string ClientRpcReceiveParams_FullName = typeof(ClientRpcReceiveParams).FullName;
         public static readonly string ServerRpcSendParams_FullName = typeof(ServerRpcSendParams).FullName;

Editor/CodeGen/INetworkMessageILPP.cs

@@ -17,7 +17,7 @@ namespace Unity.Netcode.Editor.CodeGen
     {
         public override ILPPInterface GetInstance() => this;
 
-        public override bool WillProcess(ICompiledAssembly compiledAssembly) => compiledAssembly.Name == CodeGenHelpers.RuntimeAssemblyName;
+        public override bool WillProcess(ICompiledAssembly compiledAssembly) => compiledAssembly.Name == CodeGenHelpers.RuntimeAssemblyName || compiledAssembly.Name == CodeGenHelpers.ComponentsAssemblyName;
 
         private readonly List<DiagnosticMessage> m_Diagnostics = new List<DiagnosticMessage>();
 

Editor/CodeGen/NetworkBehaviourILPP.cs

@@ -31,6 +31,43 @@ namespace Unity.Netcode.Editor.CodeGen
 
         private readonly List<DiagnosticMessage> m_Diagnostics = new List<DiagnosticMessage>();
 
+        public void AddWrappedType(TypeReference wrappedType)
+        {
+            if (!m_WrappedNetworkVariableTypes.Contains(wrappedType))
+            {
+                m_WrappedNetworkVariableTypes.Add(wrappedType);
+
+                var resolved = wrappedType.Resolve();
+                if (resolved != null)
+                {
+                    if (resolved.FullName == "System.Collections.Generic.List`1")
+                    {
+                        AddWrappedType(((GenericInstanceType)wrappedType).GenericArguments[0]);
+                    }
+                    if (resolved.FullName == "System.Collections.Generic.HashSet`1")
+                    {
+                        AddWrappedType(((GenericInstanceType)wrappedType).GenericArguments[0]);
+                    }
+                    else if (resolved.FullName == "System.Collections.Generic.Dictionary`2")
+                    {
+                        AddWrappedType(((GenericInstanceType)wrappedType).GenericArguments[0]);
+                        AddWrappedType(((GenericInstanceType)wrappedType).GenericArguments[1]);
+                    }
+#if UNITY_NETCODE_NATIVE_COLLECTION_SUPPORT
+                    else if (resolved.FullName == "Unity.Collections.NativeHashSet`1")
+                    {
+                        AddWrappedType(((GenericInstanceType)wrappedType).GenericArguments[0]);
+                    }
+                    else if (resolved.FullName == "Unity.Collections.NativeHashMap`2")
+                    {
+                        AddWrappedType(((GenericInstanceType)wrappedType).GenericArguments[0]);
+                        AddWrappedType(((GenericInstanceType)wrappedType).GenericArguments[1]);
+                    }
+#endif
+                }
+            }
+        }
+
         public override ILPostProcessResult Process(ICompiledAssembly compiledAssembly)
         {
             if (!WillProcess(compiledAssembly))
@@ -87,10 +124,7 @@ namespace Unity.Netcode.Editor.CodeGen
                                 if (attribute.AttributeType.Name == nameof(GenerateSerializationForTypeAttribute))
                                 {
                                     var wrappedType = mainModule.ImportReference((TypeReference)attribute.ConstructorArguments[0].Value);
-                                    if (!m_WrappedNetworkVariableTypes.Contains(wrappedType))
-                                    {
-                                        m_WrappedNetworkVariableTypes.Add(wrappedType);
-                                    }
+                                    AddWrappedType(wrappedType);
                                 }
                             }
 
@@ -101,10 +135,7 @@ namespace Unity.Netcode.Editor.CodeGen
                                     if (attribute.AttributeType.Name == nameof(GenerateSerializationForTypeAttribute))
                                     {
                                         var wrappedType = mainModule.ImportReference((TypeReference)attribute.ConstructorArguments[0].Value);
-                                        if (!m_WrappedNetworkVariableTypes.Contains(wrappedType))
-                                        {
-                                            m_WrappedNetworkVariableTypes.Add(wrappedType);
-                                        }
+                                        AddWrappedType(wrappedType);
                                     }
                                 }
                             }
@@ -241,6 +272,36 @@ namespace Unity.Netcode.Editor.CodeGen
                     serializeMethod?.GenericArguments.Add(wrappedType);
                     equalityMethod.GenericArguments.Add(wrappedType);
                 }
+                else if (type.Resolve().FullName == "System.Collections.Generic.List`1")
+                {
+                    var wrappedType = ((GenericInstanceType)type).GenericArguments[0];
+                    serializeMethod = new GenericInstanceMethod(m_NetworkVariableSerializationTypes_InitializeSerializer_List_MethodRef);
+
+                    equalityMethod = new GenericInstanceMethod(m_NetworkVariableSerializationTypes_InitializeEqualityChecker_List_MethodRef);
+                    serializeMethod.GenericArguments.Add(wrappedType);
+                    equalityMethod.GenericArguments.Add(wrappedType);
+                }
+                else if (type.Resolve().FullName == "System.Collections.Generic.HashSet`1")
+                {
+                    var wrappedType = ((GenericInstanceType)type).GenericArguments[0];
+                    serializeMethod = new GenericInstanceMethod(m_NetworkVariableSerializationTypes_InitializeSerializer_HashSet_MethodRef);
+
+                    equalityMethod = new GenericInstanceMethod(m_NetworkVariableSerializationTypes_InitializeEqualityChecker_HashSet_MethodRef);
+                    serializeMethod.GenericArguments.Add(wrappedType);
+                    equalityMethod.GenericArguments.Add(wrappedType);
+                }
+                else if (type.Resolve().FullName == "System.Collections.Generic.Dictionary`2")
+                {
+                    var wrappedKeyType = ((GenericInstanceType)type).GenericArguments[0];
+                    var wrappedValType = ((GenericInstanceType)type).GenericArguments[1];
+                    serializeMethod = new GenericInstanceMethod(m_NetworkVariableSerializationTypes_InitializeSerializer_Dictionary_MethodRef);
+
+                    equalityMethod = new GenericInstanceMethod(m_NetworkVariableSerializationTypes_InitializeEqualityChecker_Dictionary_MethodRef);
+                    serializeMethod.GenericArguments.Add(wrappedKeyType);
+                    serializeMethod.GenericArguments.Add(wrappedValType);
+                    equalityMethod.GenericArguments.Add(wrappedKeyType);
+                    equalityMethod.GenericArguments.Add(wrappedValType);
+                }
 #if UNITY_NETCODE_NATIVE_COLLECTION_SUPPORT
                 else if (type.Resolve().FullName == "Unity.Collections.NativeList`1")
                 {
@@ -267,12 +328,30 @@ namespace Unity.Netcode.Editor.CodeGen
                         equalityMethod = new GenericInstanceMethod(m_NetworkVariableSerializationTypes_InitializeEqualityChecker_UnmanagedValueEqualsList_MethodRef);
                     }
 
-                    if (serializeMethod != null)
-                    {
-                        serializeMethod.GenericArguments.Add(wrappedType);
-                    }
+                    serializeMethod?.GenericArguments.Add(wrappedType);
                     equalityMethod.GenericArguments.Add(wrappedType);
                 }
+                else if (type.Resolve().FullName == "Unity.Collections.NativeHashSet`1")
+                {
+                    var wrappedType = ((GenericInstanceType)type).GenericArguments[0];
+                    serializeMethod = new GenericInstanceMethod(m_NetworkVariableSerializationTypes_InitializeSerializer_NativeHashSet_MethodRef);
+
+                    equalityMethod = new GenericInstanceMethod(m_NetworkVariableSerializationTypes_InitializeEqualityChecker_NativeHashSet_MethodRef);
+                    serializeMethod.GenericArguments.Add(wrappedType);
+                    equalityMethod.GenericArguments.Add(wrappedType);
+                }
+                else if (type.Resolve().FullName == "Unity.Collections.NativeHashMap`2")
+                {
+                    var wrappedKeyType = ((GenericInstanceType)type).GenericArguments[0];
+                    var wrappedValType = ((GenericInstanceType)type).GenericArguments[1];
+                    serializeMethod = new GenericInstanceMethod(m_NetworkVariableSerializationTypes_InitializeSerializer_NativeHashMap_MethodRef);
+
+                    equalityMethod = new GenericInstanceMethod(m_NetworkVariableSerializationTypes_InitializeEqualityChecker_NativeHashMap_MethodRef);
+                    serializeMethod.GenericArguments.Add(wrappedKeyType);
+                    serializeMethod.GenericArguments.Add(wrappedValType);
+                    equalityMethod.GenericArguments.Add(wrappedKeyType);
+                    equalityMethod.GenericArguments.Add(wrappedValType);
+                }
 #endif
                 else if (type.IsValueType)
                 {
@@ -363,11 +442,14 @@ namespace Unity.Netcode.Editor.CodeGen
         private FieldReference m_NetworkManager_LogLevel_FieldRef;
         private MethodReference m_NetworkBehaviour___registerRpc_MethodRef;
         private TypeReference m_NetworkBehaviour_TypeRef;
+        private TypeReference m_AttributeParamsType_TypeRef;
         private TypeReference m_NetworkVariableBase_TypeRef;
         private MethodReference m_NetworkVariableBase_Initialize_MethodRef;
         private MethodReference m_NetworkBehaviour___nameNetworkVariable_MethodRef;
         private MethodReference m_NetworkBehaviour_beginSendServerRpc_MethodRef;
         private MethodReference m_NetworkBehaviour_endSendServerRpc_MethodRef;
+        private MethodReference m_NetworkBehaviour_beginSendRpc_MethodRef;
+        private MethodReference m_NetworkBehaviour_endSendRpc_MethodRef;
         private MethodReference m_NetworkBehaviour_beginSendClientRpc_MethodRef;
         private MethodReference m_NetworkBehaviour_endSendClientRpc_MethodRef;
         private FieldReference m_NetworkBehaviour_rpc_exec_stage_FieldRef;
@@ -378,9 +460,13 @@ namespace Unity.Netcode.Editor.CodeGen
         private TypeReference m_RpcParams_TypeRef;
         private FieldReference m_RpcParams_Server_FieldRef;
         private FieldReference m_RpcParams_Client_FieldRef;
+        private FieldReference m_RpcParams_Ext_FieldRef;
         private TypeReference m_ServerRpcParams_TypeRef;
         private FieldReference m_ServerRpcParams_Receive_FieldRef;
         private FieldReference m_ServerRpcParams_Receive_SenderClientId_FieldRef;
+        private FieldReference m_UniversalRpcParams_Receive_FieldRef;
+        private FieldReference m_UniversalRpcParams_Receive_SenderClientId_FieldRef;
+        private TypeReference m_UniversalRpcParams_TypeRef;
         private TypeReference m_ClientRpcParams_TypeRef;
         private MethodReference m_NetworkVariableSerializationTypes_InitializeSerializer_UnmanagedByMemcpy_MethodRef;
         private MethodReference m_NetworkVariableSerializationTypes_InitializeSerializer_UnmanagedByMemcpyArray_MethodRef;
@@ -391,7 +477,12 @@ namespace Unity.Netcode.Editor.CodeGen
         private MethodReference m_NetworkVariableSerializationTypes_InitializeSerializer_UnmanagedINetworkSerializableArray_MethodRef;
 #if UNITY_NETCODE_NATIVE_COLLECTION_SUPPORT
         private MethodReference m_NetworkVariableSerializationTypes_InitializeSerializer_UnmanagedINetworkSerializableList_MethodRef;
+        private MethodReference m_NetworkVariableSerializationTypes_InitializeSerializer_NativeHashSet_MethodRef;
+        private MethodReference m_NetworkVariableSerializationTypes_InitializeSerializer_NativeHashMap_MethodRef;
 #endif
+        private MethodReference m_NetworkVariableSerializationTypes_InitializeSerializer_List_MethodRef;
+        private MethodReference m_NetworkVariableSerializationTypes_InitializeSerializer_HashSet_MethodRef;
+        private MethodReference m_NetworkVariableSerializationTypes_InitializeSerializer_Dictionary_MethodRef;
         private MethodReference m_NetworkVariableSerializationTypes_InitializeSerializer_ManagedINetworkSerializable_MethodRef;
         private MethodReference m_NetworkVariableSerializationTypes_InitializeSerializer_FixedString_MethodRef;
         private MethodReference m_NetworkVariableSerializationTypes_InitializeSerializer_FixedStringArray_MethodRef;
@@ -408,7 +499,12 @@ namespace Unity.Netcode.Editor.CodeGen
         private MethodReference m_NetworkVariableSerializationTypes_InitializeEqualityChecker_UnmanagedValueEqualsArray_MethodRef;
 #if UNITY_NETCODE_NATIVE_COLLECTION_SUPPORT
         private MethodReference m_NetworkVariableSerializationTypes_InitializeEqualityChecker_UnmanagedValueEqualsList_MethodRef;
+        private MethodReference m_NetworkVariableSerializationTypes_InitializeEqualityChecker_NativeHashSet_MethodRef;
+        private MethodReference m_NetworkVariableSerializationTypes_InitializeEqualityChecker_NativeHashMap_MethodRef;
 #endif
+        private MethodReference m_NetworkVariableSerializationTypes_InitializeEqualityChecker_List_MethodRef;
+        private MethodReference m_NetworkVariableSerializationTypes_InitializeEqualityChecker_HashSet_MethodRef;
+        private MethodReference m_NetworkVariableSerializationTypes_InitializeEqualityChecker_Dictionary_MethodRef;
         private MethodReference m_NetworkVariableSerializationTypes_InitializeEqualityChecker_ManagedClassEquals_MethodRef;
 
         private MethodReference m_RuntimeInitializeOnLoadAttribute_Ctor;
@@ -495,6 +591,8 @@ namespace Unity.Netcode.Editor.CodeGen
         private const string k_NetworkBehaviour_NetworkVariableFields = nameof(NetworkBehaviour.NetworkVariableFields);
         private const string k_NetworkBehaviour_beginSendServerRpc = nameof(NetworkBehaviour.__beginSendServerRpc);
         private const string k_NetworkBehaviour_endSendServerRpc = nameof(NetworkBehaviour.__endSendServerRpc);
+        private const string k_NetworkBehaviour_beginSendRpc = nameof(NetworkBehaviour.__beginSendRpc);
+        private const string k_NetworkBehaviour_endSendRpc = nameof(NetworkBehaviour.__endSendRpc);
         private const string k_NetworkBehaviour_beginSendClientRpc = nameof(NetworkBehaviour.__beginSendClientRpc);
         private const string k_NetworkBehaviour_endSendClientRpc = nameof(NetworkBehaviour.__endSendClientRpc);
         private const string k_NetworkBehaviour___initializeVariables = nameof(NetworkBehaviour.__initializeVariables);
@@ -511,8 +609,11 @@ namespace Unity.Netcode.Editor.CodeGen
         private const string k_ServerRpcAttribute_RequireOwnership = nameof(ServerRpcAttribute.RequireOwnership);
         private const string k_RpcParams_Server = nameof(__RpcParams.Server);
         private const string k_RpcParams_Client = nameof(__RpcParams.Client);
+        private const string k_RpcParams_Ext = nameof(__RpcParams.Ext);
         private const string k_ServerRpcParams_Receive = nameof(ServerRpcParams.Receive);
+        private const string k_RpcParams_Receive = nameof(RpcParams.Receive);
         private const string k_ServerRpcReceiveParams_SenderClientId = nameof(ServerRpcReceiveParams.SenderClientId);
+        private const string k_RpcReceiveParams_SenderClientId = nameof(RpcReceiveParams.SenderClientId);
 
         // CodeGen cannot reference the collections assembly to do a typeof() on it due to a bug that causes that to crash.
         private const string k_INativeListBool_FullName = "Unity.Collections.INativeList`1<System.Byte>";
@@ -545,13 +646,20 @@ namespace Unity.Netcode.Editor.CodeGen
             TypeDefinition rpcParamsTypeDef = null;
             TypeDefinition serverRpcParamsTypeDef = null;
             TypeDefinition clientRpcParamsTypeDef = null;
+            TypeDefinition universalRpcParamsTypeDef = null;
             TypeDefinition fastBufferWriterTypeDef = null;
             TypeDefinition fastBufferReaderTypeDef = null;
             TypeDefinition networkVariableSerializationTypesTypeDef = null;
             TypeDefinition bytePackerTypeDef = null;
             TypeDefinition byteUnpackerTypeDef = null;
+            TypeDefinition attributeParamsType = null;
             foreach (var netcodeTypeDef in m_NetcodeModule.GetAllTypes())
             {
+                if (attributeParamsType == null && netcodeTypeDef.Name == nameof(RpcAttribute.RpcAttributeParams))
+                {
+                    attributeParamsType = netcodeTypeDef;
+                    continue;
+                }
                 if (networkManagerTypeDef == null && netcodeTypeDef.Name == nameof(NetworkManager))
                 {
                     networkManagerTypeDef = netcodeTypeDef;
@@ -588,6 +696,12 @@ namespace Unity.Netcode.Editor.CodeGen
                     continue;
                 }
 
+                if (universalRpcParamsTypeDef == null && netcodeTypeDef.Name == nameof(RpcParams))
+                {
+                    universalRpcParamsTypeDef = netcodeTypeDef;
+                    continue;
+                }
+
                 if (clientRpcParamsTypeDef == null && netcodeTypeDef.Name == nameof(ClientRpcParams))
                 {
                     clientRpcParamsTypeDef = netcodeTypeDef;
@@ -662,6 +776,8 @@ namespace Unity.Netcode.Editor.CodeGen
                 }
             }
 
+            m_AttributeParamsType_TypeRef = moduleDefinition.ImportReference(attributeParamsType);
+
             foreach (var fieldDef in networkManagerTypeDef.Fields)
             {
                 switch (fieldDef.Name)
@@ -696,6 +812,12 @@ namespace Unity.Netcode.Editor.CodeGen
                     case k_NetworkBehaviour_endSendServerRpc:
                         m_NetworkBehaviour_endSendServerRpc_MethodRef = moduleDefinition.ImportReference(methodDef);
                         break;
+                    case k_NetworkBehaviour_beginSendRpc:
+                        m_NetworkBehaviour_beginSendRpc_MethodRef = moduleDefinition.ImportReference(methodDef);
+                        break;
+                    case k_NetworkBehaviour_endSendRpc:
+                        m_NetworkBehaviour_endSendRpc_MethodRef = moduleDefinition.ImportReference(methodDef);
+                        break;
                     case k_NetworkBehaviour_beginSendClientRpc:
                         m_NetworkBehaviour_beginSendClientRpc_MethodRef = moduleDefinition.ImportReference(methodDef);
                         break;
@@ -763,6 +885,9 @@ namespace Unity.Netcode.Editor.CodeGen
                     case k_RpcParams_Client:
                         m_RpcParams_Client_FieldRef = moduleDefinition.ImportReference(fieldDef);
                         break;
+                    case k_RpcParams_Ext:
+                        m_RpcParams_Ext_FieldRef = moduleDefinition.ImportReference(fieldDef);
+                        break;
                 }
             }
 
@@ -786,6 +911,26 @@ namespace Unity.Netcode.Editor.CodeGen
                         break;
                 }
             }
+            m_UniversalRpcParams_TypeRef = moduleDefinition.ImportReference(universalRpcParamsTypeDef);
+            foreach (var fieldDef in rpcParamsTypeDef.Fields)
+            {
+                switch (fieldDef.Name)
+                {
+                    case k_RpcParams_Receive:
+                        foreach (var recvFieldDef in fieldDef.FieldType.Resolve().Fields)
+                        {
+                            switch (recvFieldDef.Name)
+                            {
+                                case k_RpcReceiveParams_SenderClientId:
+                                    m_UniversalRpcParams_Receive_SenderClientId_FieldRef = moduleDefinition.ImportReference(recvFieldDef);
+                                    break;
+                            }
+                        }
+
+                        m_UniversalRpcParams_Receive_FieldRef = moduleDefinition.ImportReference(fieldDef);
+                        break;
+                }
+            }
 
             m_ClientRpcParams_TypeRef = moduleDefinition.ImportReference(clientRpcParamsTypeDef);
             m_FastBufferWriter_TypeRef = moduleDefinition.ImportReference(fastBufferWriterTypeDef);
@@ -884,7 +1029,22 @@ namespace Unity.Netcode.Editor.CodeGen
                     case nameof(NetworkVariableSerializationTypes.InitializeSerializer_UnmanagedINetworkSerializableList):
                         m_NetworkVariableSerializationTypes_InitializeSerializer_UnmanagedINetworkSerializableList_MethodRef = method;
                         break;
+                    case nameof(NetworkVariableSerializationTypes.InitializeSerializer_NativeHashSet):
+                        m_NetworkVariableSerializationTypes_InitializeSerializer_NativeHashSet_MethodRef = method;
+                        break;
+                    case nameof(NetworkVariableSerializationTypes.InitializeSerializer_NativeHashMap):
+                        m_NetworkVariableSerializationTypes_InitializeSerializer_NativeHashMap_MethodRef = method;
+                        break;
 #endif
+                    case nameof(NetworkVariableSerializationTypes.InitializeSerializer_List):
+                        m_NetworkVariableSerializationTypes_InitializeSerializer_List_MethodRef = method;
+                        break;
+                    case nameof(NetworkVariableSerializationTypes.InitializeSerializer_HashSet):
+                        m_NetworkVariableSerializationTypes_InitializeSerializer_HashSet_MethodRef = method;
+                        break;
+                    case nameof(NetworkVariableSerializationTypes.InitializeSerializer_Dictionary):
+                        m_NetworkVariableSerializationTypes_InitializeSerializer_Dictionary_MethodRef = method;
+                        break;
                     case nameof(NetworkVariableSerializationTypes.InitializeSerializer_ManagedINetworkSerializable):
                         m_NetworkVariableSerializationTypes_InitializeSerializer_ManagedINetworkSerializable_MethodRef = method;
                         break;
@@ -915,7 +1075,22 @@ namespace Unity.Netcode.Editor.CodeGen
                     case nameof(NetworkVariableSerializationTypes.InitializeEqualityChecker_UnmanagedIEquatableList):
                         m_NetworkVariableSerializationTypes_InitializeEqualityChecker_UnmanagedIEquatableList_MethodRef = method;
                         break;
+                    case nameof(NetworkVariableSerializationTypes.InitializeEqualityChecker_NativeHashSet):
+                        m_NetworkVariableSerializationTypes_InitializeEqualityChecker_NativeHashSet_MethodRef = method;
+                        break;
+                    case nameof(NetworkVariableSerializationTypes.InitializeEqualityChecker_NativeHashMap):
+                        m_NetworkVariableSerializationTypes_InitializeEqualityChecker_NativeHashMap_MethodRef = method;
+                        break;
 #endif
+                    case nameof(NetworkVariableSerializationTypes.InitializeEqualityChecker_List):
+                        m_NetworkVariableSerializationTypes_InitializeEqualityChecker_List_MethodRef = method;
+                        break;
+                    case nameof(NetworkVariableSerializationTypes.InitializeEqualityChecker_HashSet):
+                        m_NetworkVariableSerializationTypes_InitializeEqualityChecker_HashSet_MethodRef = method;
+                        break;
+                    case nameof(NetworkVariableSerializationTypes.InitializeEqualityChecker_Dictionary):
+                        m_NetworkVariableSerializationTypes_InitializeEqualityChecker_Dictionary_MethodRef = method;
+                        break;
                     case nameof(NetworkVariableSerializationTypes.InitializeEqualityChecker_UnmanagedValueEquals):
                         m_NetworkVariableSerializationTypes_InitializeEqualityChecker_UnmanagedValueEquals_MethodRef = method;
                         break;
@@ -1190,10 +1365,7 @@ namespace Unity.Netcode.Editor.CodeGen
                                     continue;
                                 }
                                 var wrappedType = genericInstanceType.GenericArguments[idx];
-                                if (!m_WrappedNetworkVariableTypes.Contains(wrappedType))
-                                {
-                                    m_WrappedNetworkVariableTypes.Add(wrappedType);
-                                }
+                                AddWrappedType(wrappedType);
                             }
                         }
                     }
@@ -1226,10 +1398,7 @@ namespace Unity.Netcode.Editor.CodeGen
                                         continue;
                                     }
                                     var wrappedType = genericInstanceType.GenericArguments[idx];
-                                    if (!m_WrappedNetworkVariableTypes.Contains(wrappedType))
-                                    {
-                                        m_WrappedNetworkVariableTypes.Add(wrappedType);
-                                    }
+                                    AddWrappedType(wrappedType);
                                 }
                             }
                         }
@@ -1237,8 +1406,10 @@ namespace Unity.Netcode.Editor.CodeGen
                 }
             }
 
-            if (rpcHandlers.Count > 0)
+            //if (rpcHandlers.Count > 0)
             {
+
+                // This always needs to generate even if it's empty.
                 var initializeRpcsMethodDef = new MethodDefinition(
                         k_NetworkBehaviour___initializeRpcs,
                         MethodAttributes.Family | MethodAttributes.Virtual | MethodAttributes.HideBySig,
@@ -1352,7 +1523,8 @@ namespace Unity.Netcode.Editor.CodeGen
                 var customAttributeType_FullName = customAttribute.AttributeType.FullName;
 
                 if (customAttributeType_FullName == CodeGenHelpers.ServerRpcAttribute_FullName ||
-                    customAttributeType_FullName == CodeGenHelpers.ClientRpcAttribute_FullName)
+                    customAttributeType_FullName == CodeGenHelpers.ClientRpcAttribute_FullName ||
+                    customAttributeType_FullName == CodeGenHelpers.RpcAttribute_FullName)
                 {
                     bool isValid = true;
 
@@ -1387,6 +1559,13 @@ namespace Unity.Netcode.Editor.CodeGen
                         isValid = false;
                     }
 
+                    if (customAttributeType_FullName == CodeGenHelpers.RpcAttribute_FullName &&
+                        !methodDefinition.Name.EndsWith("Rpc", StringComparison.OrdinalIgnoreCase))
+                    {
+                        m_Diagnostics.AddError(methodDefinition, "Rpc method must end with 'Rpc' suffix!");
+                        isValid = false;
+                    }
+
                     if (customAttributeType_FullName == CodeGenHelpers.ClientRpcAttribute_FullName &&
                         !methodDefinition.Name.EndsWith("ClientRpc", StringComparison.OrdinalIgnoreCase))
                     {
@@ -1409,11 +1588,15 @@ namespace Unity.Netcode.Editor.CodeGen
             {
                 if (methodDefinition.Name.EndsWith("ServerRpc", StringComparison.OrdinalIgnoreCase))
                 {
-                    m_Diagnostics.AddError(methodDefinition, "ServerRpc method must be marked with 'ServerRpc' attribute!");
+                    m_Diagnostics.AddError(methodDefinition, $"ServerRpc method {methodDefinition} must be marked with 'ServerRpc' attribute!");
                 }
                 else if (methodDefinition.Name.EndsWith("ClientRpc", StringComparison.OrdinalIgnoreCase))
                 {
-                    m_Diagnostics.AddError(methodDefinition, "ClientRpc method must be marked with 'ClientRpc' attribute!");
+                    m_Diagnostics.AddError(methodDefinition, $"ClientRpc method {methodDefinition} must be marked with 'ClientRpc' attribute!");
+                }
+                else if (methodDefinition.Name.EndsWith("ExtRpc", StringComparison.OrdinalIgnoreCase))
+                {
+                    m_Diagnostics.AddError(methodDefinition, $"Ext Rpc method {methodDefinition} must be marked with 'ExtRpc' attribute!");
                 }
 
                 return null;
@@ -1885,8 +2068,17 @@ namespace Unity.Netcode.Editor.CodeGen
             var instructions = new List<Instruction>();
             var processor = methodDefinition.Body.GetILProcessor();
             var isServerRpc = rpcAttribute.AttributeType.FullName == CodeGenHelpers.ServerRpcAttribute_FullName;
+            var isClientRpc = rpcAttribute.AttributeType.FullName == CodeGenHelpers.ClientRpcAttribute_FullName;
+            var isGenericRpc = rpcAttribute.AttributeType.FullName == CodeGenHelpers.RpcAttribute_FullName;
             var requireOwnership = true; // default value MUST be == `ServerRpcAttribute.RequireOwnership`
             var rpcDelivery = RpcDelivery.Reliable; // default value MUST be == `RpcAttribute.Delivery`
+            var defaultTarget = SendTo.Everyone;
+            var allowTargetOverride = false;
+
+            if (isGenericRpc)
+            {
+                defaultTarget = (SendTo)rpcAttribute.ConstructorArguments[0].Value;
+            }
             foreach (var attrField in rpcAttribute.Fields)
             {
                 switch (attrField.Name)
@@ -1897,6 +2089,9 @@ namespace Unity.Netcode.Editor.CodeGen
                     case k_ServerRpcAttribute_RequireOwnership:
                         requireOwnership = attrField.Argument.Type == typeSystem.Boolean && (bool)attrField.Argument.Value;
                         break;
+                    case nameof(RpcAttribute.AllowTargetOverride):
+                        allowTargetOverride = attrField.Argument.Type == typeSystem.Boolean && (bool)attrField.Argument.Value;
+                        break;
                 }
             }
 
@@ -1904,7 +2099,33 @@ namespace Unity.Netcode.Editor.CodeGen
             var hasRpcParams =
                 paramCount > 0 &&
                 ((isServerRpc && methodDefinition.Parameters[paramCount - 1].ParameterType.FullName == CodeGenHelpers.ServerRpcParams_FullName) ||
-                 (!isServerRpc && methodDefinition.Parameters[paramCount - 1].ParameterType.FullName == CodeGenHelpers.ClientRpcParams_FullName));
+                 (isClientRpc && methodDefinition.Parameters[paramCount - 1].ParameterType.FullName == CodeGenHelpers.ClientRpcParams_FullName) ||
+                 (isGenericRpc && methodDefinition.Parameters[paramCount - 1].ParameterType.FullName == CodeGenHelpers.RpcParams_FullName));
+
+            if (isGenericRpc && defaultTarget == SendTo.SpecifiedInParams)
+            {
+                if (!hasRpcParams)
+                {
+                    m_Diagnostics.AddError($"{methodDefinition}: {nameof(SendTo)}.{nameof(SendTo.SpecifiedInParams)} cannot be used without a final parameter of type {CodeGenHelpers.RpcParams_FullName}.");
+                }
+
+                foreach (var attrField in rpcAttribute.Fields)
+                {
+                    switch (attrField.Name)
+                    {
+                        case nameof(RpcAttribute.AllowTargetOverride):
+                            m_Diagnostics.AddWarning($"{methodDefinition}: {nameof(RpcAttribute.AllowTargetOverride)} is ignored with {nameof(SendTo)}.{nameof(SendTo.SpecifiedInParams)}");
+                            break;
+                    }
+                }
+            }
+            if (isGenericRpc && allowTargetOverride)
+            {
+                if (!hasRpcParams)
+                {
+                    m_Diagnostics.AddError($"{methodDefinition}: {nameof(RpcAttribute.AllowTargetOverride)} cannot be used without a final parameter of type {CodeGenHelpers.RpcParams_FullName}.");
+                }
+            }
 
             methodDefinition.Body.InitLocals = true;
             // NetworkManager networkManager;
@@ -1917,10 +2138,17 @@ namespace Unity.Netcode.Editor.CodeGen
             // XXXRpcParams
             if (!hasRpcParams)
             {
-                methodDefinition.Body.Variables.Add(new VariableDefinition(isServerRpc ? m_ServerRpcParams_TypeRef : m_ClientRpcParams_TypeRef));
+                methodDefinition.Body.Variables.Add(new VariableDefinition(isServerRpc ? m_ServerRpcParams_TypeRef : (isClientRpc ? m_ClientRpcParams_TypeRef : m_UniversalRpcParams_TypeRef)));
             }
             int rpcParamsIdx = !hasRpcParams ? methodDefinition.Body.Variables.Count - 1 : -1;
 
+            if (isGenericRpc)
+            {
+                methodDefinition.Body.Variables.Add(new VariableDefinition(m_AttributeParamsType_TypeRef));
+            }
+
+            int rpcAttributeParamsIdx = isGenericRpc ? methodDefinition.Body.Variables.Count - 1 : -1;
+
             {
                 var returnInstr = processor.Create(OpCodes.Ret);
                 var lastInstr = processor.Create(OpCodes.Nop);
@@ -1950,20 +2178,23 @@ namespace Unity.Netcode.Editor.CodeGen
                 // if (__rpc_exec_stage != __RpcExecStage.Client) -> ClientRpc
                 instructions.Add(processor.Create(OpCodes.Ldarg_0));
                 instructions.Add(processor.Create(OpCodes.Ldfld, m_NetworkBehaviour_rpc_exec_stage_FieldRef));
-                instructions.Add(processor.Create(OpCodes.Ldc_I4, (int)(isServerRpc ? NetworkBehaviour.__RpcExecStage.Server : NetworkBehaviour.__RpcExecStage.Client)));
+                instructions.Add(processor.Create(OpCodes.Ldc_I4, (int)NetworkBehaviour.__RpcExecStage.Execute));
                 instructions.Add(processor.Create(OpCodes.Ceq));
                 instructions.Add(processor.Create(OpCodes.Ldc_I4, 0));
                 instructions.Add(processor.Create(OpCodes.Ceq));
                 instructions.Add(processor.Create(OpCodes.Brfalse, lastInstr));
 
-                // if (networkManager.IsClient || networkManager.IsHost) { ... } -> ServerRpc
-                // if (networkManager.IsServer || networkManager.IsHost) { ... } -> ClientRpc
-                instructions.Add(processor.Create(OpCodes.Ldloc, netManLocIdx));
-                instructions.Add(processor.Create(OpCodes.Callvirt, isServerRpc ? m_NetworkManager_getIsClient_MethodRef : m_NetworkManager_getIsServer_MethodRef));
-                instructions.Add(processor.Create(OpCodes.Brtrue, beginInstr));
-                instructions.Add(processor.Create(OpCodes.Ldloc, netManLocIdx));
-                instructions.Add(processor.Create(OpCodes.Callvirt, m_NetworkManager_getIsHost_MethodRef));
-                instructions.Add(processor.Create(OpCodes.Brfalse, lastInstr));
+                if (!isGenericRpc)
+                {
+                    // if (networkManager.IsClient || networkManager.IsHost) { ... } -> ServerRpc
+                    // if (networkManager.IsServer || networkManager.IsHost) { ... } -> ClientRpc
+                    instructions.Add(processor.Create(OpCodes.Ldloc, netManLocIdx));
+                    instructions.Add(processor.Create(OpCodes.Callvirt, isServerRpc ? m_NetworkManager_getIsClient_MethodRef : m_NetworkManager_getIsServer_MethodRef));
+                    instructions.Add(processor.Create(OpCodes.Brtrue, beginInstr));
+                    instructions.Add(processor.Create(OpCodes.Ldloc, netManLocIdx));
+                    instructions.Add(processor.Create(OpCodes.Callvirt, m_NetworkManager_getIsHost_MethodRef));
+                    instructions.Add(processor.Create(OpCodes.Brfalse, lastInstr));
+                }
 
                 instructions.Add(beginInstr);
 
@@ -2025,7 +2256,7 @@ namespace Unity.Netcode.Editor.CodeGen
                     instructions.Add(processor.Create(OpCodes.Call, m_NetworkBehaviour_beginSendServerRpc_MethodRef));
                     instructions.Add(processor.Create(OpCodes.Stloc, bufWriterLocIdx));
                 }
-                else
+                else if (isClientRpc)
                 {
                     // ClientRpc
 
@@ -2045,6 +2276,89 @@ namespace Unity.Netcode.Editor.CodeGen
                     instructions.Add(processor.Create(OpCodes.Call, m_NetworkBehaviour_beginSendClientRpc_MethodRef));
                     instructions.Add(processor.Create(OpCodes.Stloc, bufWriterLocIdx));
                 }
+                else
+                {
+                    // Generic RPC
+
+                    // var bufferWriter = __beginSendRpc(rpcMethodId, rpcParams, rpcAttributeParams, defaultTarget, rpcDelivery);
+                    instructions.Add(processor.Create(OpCodes.Ldarg_0));
+
+                    // rpcMethodId
+                    instructions.Add(processor.Create(OpCodes.Ldc_I4, unchecked((int)rpcMethodId)));
+
+                    // rpcParams
+                    instructions.Add(hasRpcParams ? processor.Create(OpCodes.Ldarg, paramCount) : processor.Create(OpCodes.Ldloc, rpcParamsIdx));
+
+                    // rpcAttributeParams
+                    instructions.Add(processor.Create(OpCodes.Ldloca, rpcAttributeParamsIdx));
+                    instructions.Add(processor.Create(OpCodes.Initobj, m_AttributeParamsType_TypeRef));
+
+                    RpcAttribute.RpcAttributeParams dflt = default;
+                    foreach (var field in rpcAttribute.Fields)
+                    {
+                        var found = false;
+                        foreach (var attrField in m_AttributeParamsType_TypeRef.Resolve().Fields)
+                        {
+                            if (attrField.Name == field.Name)
+                            {
+                                found = true;
+                                var value = field.Argument.Value;
+                                var paramField = dflt.GetType().GetField(attrField.Name);
+                                if (value != paramField.GetValue(dflt))
+                                {
+                                    instructions.Add(processor.Create(OpCodes.Ldloca, rpcAttributeParamsIdx));
+                                    var type = value.GetType();
+                                    if (type == typeof(bool))
+                                    {
+                                        instructions.Add(processor.Create(OpCodes.Ldc_I4, (bool)value ? 1 : 0));
+                                    }
+                                    else if (type == typeof(short) || type == typeof(int) || type == typeof(ushort)
+                                       || type == typeof(byte) || type == typeof(sbyte) || type == typeof(char))
+                                    {
+                                        instructions.Add(processor.Create(OpCodes.Ldc_I4, (int)value));
+                                    }
+                                    else if (type == typeof(long) || type == typeof(ulong))
+                                    {
+                                        instructions.Add(processor.Create(OpCodes.Ldc_I8, (long)value));
+                                    }
+                                    else if (type == typeof(float))
+                                    {
+                                        instructions.Add(processor.Create(OpCodes.Ldc_R8, (float)value));
+
+                                    }
+                                    else if (type == typeof(double))
+                                    {
+                                        instructions.Add(processor.Create(OpCodes.Ldc_R8, (double)value));
+                                    }
+                                    else
+                                    {
+                                        m_Diagnostics.AddError("Unsupported attribute parameter type.");
+                                    }
+                                }
+
+                                instructions.Add(processor.Create(OpCodes.Stfld, m_MainModule.ImportReference(attrField)));
+
+                                break;
+                            }
+                        }
+
+                        if (!found)
+                        {
+                            m_Diagnostics.AddError($"{nameof(RpcAttribute)} contains field {field} which is not present in {nameof(RpcAttribute.RpcAttributeParams)}.");
+                        }
+                    }
+                    instructions.Add(processor.Create(OpCodes.Ldloc, rpcAttributeParamsIdx));
+
+                    // defaultTarget
+                    instructions.Add(processor.Create(OpCodes.Ldc_I4, (int)defaultTarget));
+
+                    // rpcDelivery
+                    instructions.Add(processor.Create(OpCodes.Ldc_I4, (int)rpcDelivery));
+
+                    // __beginSendRpc
+                    instructions.Add(processor.Create(OpCodes.Call, m_NetworkBehaviour_beginSendRpc_MethodRef));
+                    instructions.Add(processor.Create(OpCodes.Stloc, bufWriterLocIdx));
+                }
 
                 // write method parameters into stream
                 for (int paramIndex = 0; paramIndex < paramCount; ++paramIndex)
@@ -2073,7 +2387,7 @@ namespace Unity.Netcode.Editor.CodeGen
                         }
                         if (!isServerRpc)
                         {
-                            m_Diagnostics.AddError($"ClientRpcs may not accept {nameof(ServerRpcParams)} as a parameter.");
+                            m_Diagnostics.AddError($"Only ServerRpcs may accept {nameof(ServerRpcParams)} as a parameter.");
                         }
                         continue;
                     }
@@ -2084,9 +2398,22 @@ namespace Unity.Netcode.Editor.CodeGen
                         {
                             m_Diagnostics.AddError(methodDefinition, $"{nameof(ClientRpcParams)} must be the last parameter in a ClientRpc.");
                         }
-                        if (isServerRpc)
+                        if (!isClientRpc)
                         {
-                            m_Diagnostics.AddError($"ServerRpcs may not accept {nameof(ClientRpcParams)} as a parameter.");
+                            m_Diagnostics.AddError($"Only clientRpcs may accept {nameof(ClientRpcParams)} as a parameter.");
+                        }
+                        continue;
+                    }
+                    // RpcParams
+                    if (paramType.FullName == CodeGenHelpers.RpcParams_FullName)
+                    {
+                        if (paramIndex != paramCount - 1)
+                        {
+                            m_Diagnostics.AddError(methodDefinition, $"{nameof(RpcParams)} must be the last parameter in a ClientRpc.");
+                        }
+                        if (!isGenericRpc)
+                        {
+                            m_Diagnostics.AddError($"Only Rpcs may accept {nameof(RpcParams)} as a parameter.");
                         }
                         continue;
                     }
@@ -2249,7 +2576,7 @@ namespace Unity.Netcode.Editor.CodeGen
                     // __endSendServerRpc
                     instructions.Add(processor.Create(OpCodes.Call, m_NetworkBehaviour_endSendServerRpc_MethodRef));
                 }
-                else
+                else if (isClientRpc)
                 {
                     // ClientRpc
 
@@ -2277,6 +2604,41 @@ namespace Unity.Netcode.Editor.CodeGen
                     // __endSendClientRpc
                     instructions.Add(processor.Create(OpCodes.Call, m_NetworkBehaviour_endSendClientRpc_MethodRef));
                 }
+                else
+                {
+                    // Generic Rpc
+
+                    // __endSendRpc(ref bufferWriter, rpcMethodId, rpcParams, rpcAttributeParams, defaultTarget, rpcDelivery);
+                    instructions.Add(processor.Create(OpCodes.Ldarg_0));
+
+                    // bufferWriter
+                    instructions.Add(processor.Create(OpCodes.Ldloca, bufWriterLocIdx));
+
+                    // rpcMethodId
+                    instructions.Add(processor.Create(OpCodes.Ldc_I4, unchecked((int)rpcMethodId)));
+                    if (hasRpcParams)
+                    {
+                        // rpcParams
+                        instructions.Add(processor.Create(OpCodes.Ldarg, paramCount));
+                    }
+                    else
+                    {
+                        // default
+                        instructions.Add(processor.Create(OpCodes.Ldloc, rpcParamsIdx));
+                    }
+
+                    // rpcAttributeParams
+                    instructions.Add(processor.Create(OpCodes.Ldloc, rpcAttributeParamsIdx));
+
+                    // defaultTarget
+                    instructions.Add(processor.Create(OpCodes.Ldc_I4, (int)defaultTarget));
+
+                    // rpcDelivery
+                    instructions.Add(processor.Create(OpCodes.Ldc_I4, (int)rpcDelivery));
+
+                    // __endSendClientRpc
+                    instructions.Add(processor.Create(OpCodes.Call, m_NetworkBehaviour_endSendRpc_MethodRef));
+                }
 
                 instructions.Add(lastInstr);
             }
@@ -2285,25 +2647,53 @@ namespace Unity.Netcode.Editor.CodeGen
                 var returnInstr = processor.Create(OpCodes.Ret);
                 var lastInstr = processor.Create(OpCodes.Nop);
 
-                // if (__rpc_exec_stage == __RpcExecStage.Server) -> ServerRpc
-                // if (__rpc_exec_stage == __RpcExecStage.Client) -> ClientRpc
-                instructions.Add(processor.Create(OpCodes.Ldarg_0));
-                instructions.Add(processor.Create(OpCodes.Ldfld, m_NetworkBehaviour_rpc_exec_stage_FieldRef));
-                instructions.Add(processor.Create(OpCodes.Ldc_I4, (int)(isServerRpc ? NetworkBehaviour.__RpcExecStage.Server : NetworkBehaviour.__RpcExecStage.Client)));
-                instructions.Add(processor.Create(OpCodes.Ceq));
-                instructions.Add(processor.Create(OpCodes.Brfalse, returnInstr));
+                if (!isGenericRpc)
+                {
+                    // if (__rpc_exec_stage == __RpcExecStage.Execute)
+                    instructions.Add(processor.Create(OpCodes.Ldarg_0));
+                    instructions.Add(processor.Create(OpCodes.Ldfld, m_NetworkBehaviour_rpc_exec_stage_FieldRef));
+                    instructions.Add(processor.Create(OpCodes.Ldc_I4, (int)NetworkBehaviour.__RpcExecStage.Execute));
+                    instructions.Add(processor.Create(OpCodes.Ceq));
+                    instructions.Add(processor.Create(OpCodes.Brfalse, returnInstr));
 
-                // if (networkManager.IsServer || networkManager.IsHost) -> ServerRpc
-                // if (networkManager.IsClient || networkManager.IsHost) -> ClientRpc
-                instructions.Add(processor.Create(OpCodes.Ldloc, netManLocIdx));
-                instructions.Add(processor.Create(OpCodes.Callvirt, isServerRpc ? m_NetworkManager_getIsServer_MethodRef : m_NetworkManager_getIsClient_MethodRef));
-                instructions.Add(processor.Create(OpCodes.Brtrue, lastInstr));
-                instructions.Add(processor.Create(OpCodes.Ldloc, netManLocIdx));
-                instructions.Add(processor.Create(OpCodes.Callvirt, m_NetworkManager_getIsHost_MethodRef));
-                instructions.Add(processor.Create(OpCodes.Brtrue, lastInstr));
+                    // if (networkManager.IsServer || networkManager.IsHost) -> ServerRpc
+                    // if (networkManager.IsClient || networkManager.IsHost) -> ClientRpc
+                    instructions.Add(processor.Create(OpCodes.Ldloc, netManLocIdx));
+                    instructions.Add(processor.Create(OpCodes.Callvirt, isServerRpc ? m_NetworkManager_getIsServer_MethodRef : m_NetworkManager_getIsClient_MethodRef));
+                    instructions.Add(processor.Create(OpCodes.Brtrue, lastInstr));
+                    instructions.Add(processor.Create(OpCodes.Ldloc, netManLocIdx));
+                    instructions.Add(processor.Create(OpCodes.Callvirt, m_NetworkManager_getIsHost_MethodRef));
+                    instructions.Add(processor.Create(OpCodes.Brtrue, lastInstr));
+                    instructions.Add(returnInstr);
+                    instructions.Add(lastInstr);
+
+                    // This needs to be set back before executing the callback or else sending another RPC
+                    // from within an RPC will not work.
+                    // __rpc_exec_stage = __RpcExecStage.Send
+                    instructions.Add(processor.Create(OpCodes.Ldarg_0));
+                    instructions.Add(processor.Create(OpCodes.Ldc_I4, (int)NetworkBehaviour.__RpcExecStage.Send));
+                    instructions.Add(processor.Create(OpCodes.Stfld, m_NetworkBehaviour_rpc_exec_stage_FieldRef));
+                }
+                else
+                {
+                    // if (__rpc_exec_stage == __RpcExecStage.Execute)
+                    instructions.Add(processor.Create(OpCodes.Ldarg_0));
+                    instructions.Add(processor.Create(OpCodes.Ldfld, m_NetworkBehaviour_rpc_exec_stage_FieldRef));
+                    instructions.Add(processor.Create(OpCodes.Ldc_I4, (int)NetworkBehaviour.__RpcExecStage.Execute));
+                    instructions.Add(processor.Create(OpCodes.Ceq));
+                    instructions.Add(processor.Create(OpCodes.Brtrue, lastInstr));
+
+                    instructions.Add(returnInstr);
+                    instructions.Add(lastInstr);
+
+                    // This needs to be set back before executing the callback or else sending another RPC
+                    // from within an RPC will not work.
+                    // __rpc_exec_stage = __RpcExecStage.Send
+                    instructions.Add(processor.Create(OpCodes.Ldarg_0));
+                    instructions.Add(processor.Create(OpCodes.Ldc_I4, (int)NetworkBehaviour.__RpcExecStage.Send));
+                    instructions.Add(processor.Create(OpCodes.Stfld, m_NetworkBehaviour_rpc_exec_stage_FieldRef));
+                }
 
-                instructions.Add(returnInstr);
-                instructions.Add(lastInstr);
             }
 
             instructions.Reverse();
@@ -2456,6 +2846,8 @@ namespace Unity.Netcode.Editor.CodeGen
             var processor = rpcHandler.Body.GetILProcessor();
 
             var isServerRpc = rpcAttribute.AttributeType.FullName == CodeGenHelpers.ServerRpcAttribute_FullName;
+            var isCientRpc = rpcAttribute.AttributeType.FullName == CodeGenHelpers.ClientRpcAttribute_FullName;
+            var isGenericRpc = rpcAttribute.AttributeType.FullName == CodeGenHelpers.RpcAttribute_FullName;
             var requireOwnership = true; // default value MUST be == `ServerRpcAttribute.RequireOwnership`
             foreach (var attrField in rpcAttribute.Fields)
             {
@@ -2562,6 +2954,15 @@ namespace Unity.Netcode.Editor.CodeGen
                         processor.Emit(OpCodes.Stloc, localIndex);
                         continue;
                     }
+
+                    // RpcParams
+                    if (paramType.FullName == CodeGenHelpers.RpcParams_FullName)
+                    {
+                        processor.Emit(OpCodes.Ldarg_2);
+                        processor.Emit(OpCodes.Ldfld, m_RpcParams_Ext_FieldRef);
+                        processor.Emit(OpCodes.Stloc, localIndex);
+                        continue;
+                    }
                 }
 
                 Instruction jumpInstruction = null;
@@ -2688,7 +3089,7 @@ namespace Unity.Netcode.Editor.CodeGen
             // NetworkBehaviour.__rpc_exec_stage = __RpcExecStage.Server; -> ServerRpc
             // NetworkBehaviour.__rpc_exec_stage = __RpcExecStage.Client; -> ClientRpc
             processor.Emit(OpCodes.Ldarg_0);
-            processor.Emit(OpCodes.Ldc_I4, (int)(isServerRpc ? NetworkBehaviour.__RpcExecStage.Server : NetworkBehaviour.__RpcExecStage.Client));
+            processor.Emit(OpCodes.Ldc_I4, (int)(NetworkBehaviour.__RpcExecStage.Execute));
             processor.Emit(OpCodes.Stfld, m_NetworkBehaviour_rpc_exec_stage_FieldRef);
 
             // NetworkBehaviour.XXXRpc(...);
@@ -2711,7 +3112,7 @@ namespace Unity.Netcode.Editor.CodeGen
 
             // NetworkBehaviour.__rpc_exec_stage = __RpcExecStage.None;
             processor.Emit(OpCodes.Ldarg_0);
-            processor.Emit(OpCodes.Ldc_I4, (int)NetworkBehaviour.__RpcExecStage.None);
+            processor.Emit(OpCodes.Ldc_I4, (int)NetworkBehaviour.__RpcExecStage.Send);
             processor.Emit(OpCodes.Stfld, m_NetworkBehaviour_rpc_exec_stage_FieldRef);
 
             processor.Emit(OpCodes.Ret);

Editor/CodeGen/RuntimeAccessModifiersILPP.cs

@@ -2,6 +2,7 @@ using System.Collections.Generic;
 using System.IO;
 using Mono.Cecil;
 using Mono.Cecil.Cil;
+using Mono.Cecil.Rocks;
 using Unity.CompilationPipeline.Common.Diagnostics;
 using Unity.CompilationPipeline.Common.ILPostProcessing;
 using ILPPInterface = Unity.CompilationPipeline.Common.ILPostProcessing.ILPostProcessor;
@@ -52,6 +53,15 @@ namespace Unity.Netcode.Editor.CodeGen
                         case nameof(NetworkBehaviour):
                             ProcessNetworkBehaviour(typeDefinition);
                             break;
+                        case nameof(RpcAttribute):
+                            foreach (var methodDefinition in typeDefinition.GetConstructors())
+                            {
+                                if (methodDefinition.Parameters.Count == 0)
+                                {
+                                    methodDefinition.IsPublic = true;
+                                }
+                            }
+                            break;
                         case nameof(__RpcParams):
                         case nameof(RpcFallbackSerialization):
                             typeDefinition.IsPublic = true;
@@ -154,6 +164,8 @@ namespace Unity.Netcode.Editor.CodeGen
                     methodDefinition.Name == nameof(NetworkBehaviour.__endSendServerRpc) ||
                     methodDefinition.Name == nameof(NetworkBehaviour.__beginSendClientRpc) ||
                     methodDefinition.Name == nameof(NetworkBehaviour.__endSendClientRpc) ||
+                    methodDefinition.Name == nameof(NetworkBehaviour.__beginSendRpc) ||
+                    methodDefinition.Name == nameof(NetworkBehaviour.__endSendRpc) ||
                     methodDefinition.Name == nameof(NetworkBehaviour.__initializeVariables) ||
                     methodDefinition.Name == nameof(NetworkBehaviour.__initializeRpcs) ||
                     methodDefinition.Name == nameof(NetworkBehaviour.__registerRpc) ||

Editor/Configuration/NetcodeSettingsProvider.cs

@@ -19,7 +19,7 @@ namespace Unity.Netcode.Editor.Configuration
         {
             // First parameter is the path in the Settings window.
             // Second parameter is the scope of this setting: it only appears in the Settings window for the Project scope.
-            var provider = new SettingsProvider("Project/NetcodeForGameObjects", SettingsScope.Project)
+            var provider = new SettingsProvider("Project/Multiplayer/NetcodeForGameObjects", SettingsScope.Project)
             {
                 label = "Netcode for GameObjects",
                 keywords = new[] { "netcode", "editor" },

Editor/NetworkManagerEditor.cs

@@ -30,7 +30,7 @@ namespace Unity.Netcode.Editor
         private SerializedProperty m_ProtocolVersionProperty;
         private SerializedProperty m_NetworkTransportProperty;
         private SerializedProperty m_TickRateProperty;
-        private SerializedProperty m_MaxObjectUpdatesPerTickProperty;
+        private SerializedProperty m_SessionModeProperty;
         private SerializedProperty m_ClientConnectionBufferTimeoutProperty;
         private SerializedProperty m_ConnectionApprovalProperty;
         private SerializedProperty m_EnsureNetworkVariableLengthSafetyProperty;
@@ -38,6 +38,7 @@ namespace Unity.Netcode.Editor
         private SerializedProperty m_EnableSceneManagementProperty;
         private SerializedProperty m_RecycleNetworkIdsProperty;
         private SerializedProperty m_NetworkIdRecycleDelayProperty;
+        private SerializedProperty m_SpawnTimeOutProperty;
         private SerializedProperty m_RpcHashSizeProperty;
         private SerializedProperty m_LoadSceneTimeOutProperty;
         private SerializedProperty m_PrefabsList;
@@ -96,15 +97,20 @@ namespace Unity.Netcode.Editor
             m_ProtocolVersionProperty = m_NetworkConfigProperty.FindPropertyRelative("ProtocolVersion");
             m_NetworkTransportProperty = m_NetworkConfigProperty.FindPropertyRelative("NetworkTransport");
             m_TickRateProperty = m_NetworkConfigProperty.FindPropertyRelative("TickRate");
+            m_SessionModeProperty = m_NetworkConfigProperty.FindPropertyRelative("SessionMode");
             m_ClientConnectionBufferTimeoutProperty = m_NetworkConfigProperty.FindPropertyRelative("ClientConnectionBufferTimeout");
             m_ConnectionApprovalProperty = m_NetworkConfigProperty.FindPropertyRelative("ConnectionApproval");
             m_EnsureNetworkVariableLengthSafetyProperty = m_NetworkConfigProperty.FindPropertyRelative("EnsureNetworkVariableLengthSafety");
             m_ForceSamePrefabsProperty = m_NetworkConfigProperty.FindPropertyRelative("ForceSamePrefabs");
-            m_EnableSceneManagementProperty = m_NetworkConfigProperty.FindPropertyRelative("EnableSceneManagement");
             m_RecycleNetworkIdsProperty = m_NetworkConfigProperty.FindPropertyRelative("RecycleNetworkIds");
             m_NetworkIdRecycleDelayProperty = m_NetworkConfigProperty.FindPropertyRelative("NetworkIdRecycleDelay");
-            m_RpcHashSizeProperty = m_NetworkConfigProperty.FindPropertyRelative("RpcHashSize");
+
+            m_EnableSceneManagementProperty = m_NetworkConfigProperty.FindPropertyRelative("EnableSceneManagement");
+            m_SpawnTimeOutProperty = m_NetworkConfigProperty.FindPropertyRelative("SpawnTimeout");
             m_LoadSceneTimeOutProperty = m_NetworkConfigProperty.FindPropertyRelative("LoadSceneTimeOut");
+
+
+            m_RpcHashSizeProperty = m_NetworkConfigProperty.FindPropertyRelative("RpcHashSize");
             m_PrefabsList = m_NetworkConfigProperty
                 .FindPropertyRelative(nameof(NetworkConfig.Prefabs))
                 .FindPropertyRelative(nameof(NetworkPrefabs.NetworkPrefabsLists));
@@ -124,15 +130,20 @@ namespace Unity.Netcode.Editor
             m_ProtocolVersionProperty = m_NetworkConfigProperty.FindPropertyRelative("ProtocolVersion");
             m_NetworkTransportProperty = m_NetworkConfigProperty.FindPropertyRelative("NetworkTransport");
             m_TickRateProperty = m_NetworkConfigProperty.FindPropertyRelative("TickRate");
+            m_SessionModeProperty = m_NetworkConfigProperty.FindPropertyRelative("SessionMode");
             m_ClientConnectionBufferTimeoutProperty = m_NetworkConfigProperty.FindPropertyRelative("ClientConnectionBufferTimeout");
             m_ConnectionApprovalProperty = m_NetworkConfigProperty.FindPropertyRelative("ConnectionApproval");
             m_EnsureNetworkVariableLengthSafetyProperty = m_NetworkConfigProperty.FindPropertyRelative("EnsureNetworkVariableLengthSafety");
             m_ForceSamePrefabsProperty = m_NetworkConfigProperty.FindPropertyRelative("ForceSamePrefabs");
-            m_EnableSceneManagementProperty = m_NetworkConfigProperty.FindPropertyRelative("EnableSceneManagement");
             m_RecycleNetworkIdsProperty = m_NetworkConfigProperty.FindPropertyRelative("RecycleNetworkIds");
             m_NetworkIdRecycleDelayProperty = m_NetworkConfigProperty.FindPropertyRelative("NetworkIdRecycleDelay");
-            m_RpcHashSizeProperty = m_NetworkConfigProperty.FindPropertyRelative("RpcHashSize");
+
+
+            m_EnableSceneManagementProperty = m_NetworkConfigProperty.FindPropertyRelative("EnableSceneManagement");
+            m_SpawnTimeOutProperty = m_NetworkConfigProperty.FindPropertyRelative("SpawnTimeout");
             m_LoadSceneTimeOutProperty = m_NetworkConfigProperty.FindPropertyRelative("LoadSceneTimeOut");
+
+            m_RpcHashSizeProperty = m_NetworkConfigProperty.FindPropertyRelative("RpcHashSize");
             m_PrefabsList = m_NetworkConfigProperty
                 .FindPropertyRelative(nameof(NetworkConfig.Prefabs))
                 .FindPropertyRelative(nameof(NetworkPrefabs.NetworkPrefabsLists));
@@ -153,10 +164,46 @@ namespace Unity.Netcode.Editor
                 serializedObject.Update();
                 EditorGUILayout.PropertyField(m_RunInBackgroundProperty);
                 EditorGUILayout.PropertyField(m_LogLevelProperty);
+                EditorGUILayout.PropertyField(m_SessionModeProperty);
                 EditorGUILayout.Space();
+                EditorGUILayout.LabelField("Network Settings", EditorStyles.boldLabel);
+                EditorGUILayout.PropertyField(m_ProtocolVersionProperty);
+                EditorGUILayout.PropertyField(m_NetworkTransportProperty);
+                if (m_NetworkTransportProperty.objectReferenceValue == null)
+                {
+                    EditorGUILayout.HelpBox("You have no transport selected. A transport is required for netcode to work. Which one do you want?", MessageType.Warning);
+
+                    int selection = EditorGUILayout.Popup(0, m_TransportNames);
+
+                    if (selection > 0)
+                    {
+                        ReloadTransports();
+
+                        var transportComponent = m_NetworkManager.gameObject.GetComponent(m_TransportTypes[selection - 1]) ?? m_NetworkManager.gameObject.AddComponent(m_TransportTypes[selection - 1]);
+                        m_NetworkTransportProperty.objectReferenceValue = transportComponent;
+
+                        Repaint();
+                    }
+                }
+                EditorGUILayout.PropertyField(m_TickRateProperty);
+                EditorGUILayout.PropertyField(m_SpawnTimeOutProperty);
+                EditorGUILayout.PropertyField(m_ConnectionApprovalProperty);
+                if (m_NetworkManager.NetworkConfig.ConnectionApproval)
+                {
+                    EditorGUILayout.PropertyField(m_ClientConnectionBufferTimeoutProperty);
+                }
+                EditorGUILayout.PropertyField(m_EnsureNetworkVariableLengthSafetyProperty, new GUIContent("NetworkVariable Length Safety"));
+                EditorGUILayout.PropertyField(m_RecycleNetworkIdsProperty);
+                if (m_NetworkManager.NetworkConfig.RecycleNetworkIds)
+                {
+                    EditorGUILayout.PropertyField(m_NetworkIdRecycleDelayProperty);
+                }
+                EditorGUILayout.PropertyField(m_RpcHashSizeProperty);
 
-                EditorGUILayout.PropertyField(m_PlayerPrefabProperty);
                 EditorGUILayout.Space();
+                EditorGUILayout.LabelField("Prefab Settings", EditorStyles.boldLabel);
+                EditorGUILayout.PropertyField(m_ForceSamePrefabsProperty);
+                EditorGUILayout.PropertyField(m_PlayerPrefabProperty, new GUIContent("Default Player Prefab"));
 
                 if (m_NetworkManager.NetworkConfig.HasOldPrefabList())
                 {
@@ -214,62 +261,11 @@ namespace Unity.Netcode.Editor
                     }
                     EditorGUILayout.PropertyField(m_PrefabsList);
                 }
+
                 EditorGUILayout.Space();
-
-                EditorGUILayout.LabelField("General", EditorStyles.boldLabel);
-                EditorGUILayout.PropertyField(m_ProtocolVersionProperty);
-
-                EditorGUILayout.PropertyField(m_NetworkTransportProperty);
-
-                if (m_NetworkTransportProperty.objectReferenceValue == null)
-                {
-                    EditorGUILayout.HelpBox("You have no transport selected. A transport is required for netcode to work. Which one do you want?", MessageType.Warning);
-
-                    int selection = EditorGUILayout.Popup(0, m_TransportNames);
-
-                    if (selection > 0)
-                    {
-                        ReloadTransports();
-
-                        var transportComponent = m_NetworkManager.gameObject.GetComponent(m_TransportTypes[selection - 1]) ?? m_NetworkManager.gameObject.AddComponent(m_TransportTypes[selection - 1]);
-                        m_NetworkTransportProperty.objectReferenceValue = transportComponent;
-
-                        Repaint();
-                    }
-                }
-
-                EditorGUILayout.PropertyField(m_TickRateProperty);
-
-                EditorGUILayout.LabelField("Performance", EditorStyles.boldLabel);
-
-                EditorGUILayout.PropertyField(m_EnsureNetworkVariableLengthSafetyProperty);
-
-                EditorGUILayout.LabelField("Connection", EditorStyles.boldLabel);
-                EditorGUILayout.PropertyField(m_ConnectionApprovalProperty);
-
-                using (new EditorGUI.DisabledScope(!m_NetworkManager.NetworkConfig.ConnectionApproval))
-                {
-                    EditorGUILayout.PropertyField(m_ClientConnectionBufferTimeoutProperty);
-                }
-
-                EditorGUILayout.LabelField("Spawning", EditorStyles.boldLabel);
-                EditorGUILayout.PropertyField(m_ForceSamePrefabsProperty);
-
-
-                EditorGUILayout.PropertyField(m_RecycleNetworkIdsProperty);
-
-                using (new EditorGUI.DisabledScope(!m_NetworkManager.NetworkConfig.RecycleNetworkIds))
-                {
-                    EditorGUILayout.PropertyField(m_NetworkIdRecycleDelayProperty);
-                }
-
-                EditorGUILayout.LabelField("Bandwidth", EditorStyles.boldLabel);
-                EditorGUILayout.PropertyField(m_RpcHashSizeProperty);
-
-                EditorGUILayout.LabelField("Scene Management", EditorStyles.boldLabel);
+                EditorGUILayout.LabelField("Scene Management Settings", EditorStyles.boldLabel);
                 EditorGUILayout.PropertyField(m_EnableSceneManagementProperty);
-
-                using (new EditorGUI.DisabledScope(!m_NetworkManager.NetworkConfig.EnableSceneManagement))
+                if (m_NetworkManager.NetworkConfig.EnableSceneManagement)
                 {
                     EditorGUILayout.PropertyField(m_LoadSceneTimeOutProperty);
                 }

Editor/NetworkManagerRelayIntegration.cs

@@ -0,0 +1,120 @@
+#if UNITY_2022_3_OR_NEWER && (RELAY_SDK_INSTALLED && !UNITY_WEBGL ) || (RELAY_SDK_INSTALLED && UNITY_WEBGL && UTP_TRANSPORT_2_0_ABOVE)
+using System;
+using System.Threading.Tasks;
+using Unity.Netcode.Transports.UTP;
+using Unity.Networking.Transport.Relay;
+using Unity.Services.Authentication;
+using Unity.Services.Core;
+using Unity.Services.Relay;
+using Unity.Services.Relay.Models;
+
+namespace Unity.Netcode.Editor
+{
+    /// <summary>
+    /// Integration with Unity Relay SDK and Unity Transport that support the additional buttons in the NetworkManager inspector.
+    /// This code could theoretically be used at runtime, but we would like to avoid the additional dependencies in the runtime assembly of netcode for gameobjects.
+    /// </summary>
+    public static class NetworkManagerRelayIntegration
+    {
+
+#if UNITY_WEBGL
+        private const string k_DefaultConnectionType = "wss";
+#else
+        private const string k_DefaultConnectionType = "dtls";
+#endif
+
+        /// <summary>
+        /// Easy relay integration (host): it will initialize the unity services, sign in anonymously and start the host with a new relay allocation.
+        /// Note that this will force the use of Unity Transport.
+        /// </summary>
+        /// <param name="networkManager">The network manager that will start the connection</param>
+        /// <param name="maxConnections">Maximum number of connections to the created relay.</param>
+        /// <param name="connectionType">The connection type of the <see cref="RelayServerData"/> (wss, ws, dtls or udp) </param>
+        /// <returns>The join code that a potential client can use and the allocation</returns>
+        /// <exception cref="ServicesInitializationException"> Exception when there's an error during services initialization </exception>
+        /// <exception cref="UnityProjectNotLinkedException"> Exception when the project is not linked to a cloud project id </exception>
+        /// <exception cref="CircularDependencyException"> Exception when two registered <see cref="IInitializablePackage"/> depend on the other </exception>
+        /// <exception cref="AuthenticationException"> The task fails with the exception when the task cannot complete successfully due to Authentication specific errors. </exception>
+        /// <exception cref="RequestFailedException"> See <see cref="IAuthenticationService.SignInAnonymouslyAsync"/></exception>
+        /// <exception cref="ArgumentException">Thrown when the maxConnections argument fails validation in Relay Service SDK.</exception>
+        /// <exception cref="RelayServiceException">Thrown when the request successfully reach the Relay Allocation Service but results in an error.</exception>
+        internal static async Task<(string, Allocation)> StartHostWithRelay(this NetworkManager networkManager, int maxConnections = 5)
+        {
+            var codeAndAllocation = await InitializeAndCreateAllocAsync(networkManager, maxConnections, k_DefaultConnectionType);
+            return networkManager.StartHost() ? codeAndAllocation : (null, null);
+        }
+
+        /// <summary>
+        /// Easy relay integration (server): it will initialize the unity services, sign in anonymously and start the server with a new relay allocation.
+        /// Note that this will force the use of Unity Transport.
+        /// </summary>
+        /// <param name="networkManager">The network manager that will start the connection</param>
+        /// <param name="maxConnections">Maximum number of connections to the created relay.</param>
+        /// <returns>The join code that a potential client can use and the allocation.</returns>
+        /// <exception cref="ServicesInitializationException"> Exception when there's an error during services initialization </exception>
+        /// <exception cref="UnityProjectNotLinkedException"> Exception when the project is not linked to a cloud project id </exception>
+        /// <exception cref="CircularDependencyException"> Exception when two registered <see cref="IInitializablePackage"/> depend on the other </exception>
+        /// <exception cref="AuthenticationException"> The task fails with the exception when the task cannot complete successfully due to Authentication specific errors. </exception>
+        /// <exception cref="RequestFailedException"> See <see cref="IAuthenticationService.SignInAnonymouslyAsync"/></exception>
+        /// <exception cref="ArgumentException">Thrown when the maxConnections argument fails validation in Relay Service SDK.</exception>
+        /// <exception cref="RelayServiceException">Thrown when the request successfully reach the Relay Allocation Service but results in an error.</exception>
+        internal static async Task<(string, Allocation)> StartServerWithRelay(this NetworkManager networkManager, int maxConnections = 5)
+        {
+            var codeAndAllocation = await InitializeAndCreateAllocAsync(networkManager, maxConnections, k_DefaultConnectionType);
+            return networkManager.StartServer() ? codeAndAllocation : (null, null);
+        }
+
+        /// <summary>
+        /// Easy relay integration (client): it will initialize the unity services, sign in anonymously, join the relay with the given join code and start the client.
+        /// Note that this will force the use of Unity Transport.
+        /// </summary>
+        /// <param name="networkManager">The network manager that will start the connection</param>
+        /// <param name="joinCode">The join code of the allocation</param>
+        /// <exception cref="ServicesInitializationException"> Exception when there's an error during services initialization </exception>
+        /// <exception cref="UnityProjectNotLinkedException"> Exception when the project is not linked to a cloud project id </exception>
+        /// <exception cref="CircularDependencyException"> Exception when two registered <see cref="IInitializablePackage"/> depend on the other </exception>
+        /// <exception cref="AuthenticationException"> The task fails with the exception when the task cannot complete successfully due to Authentication specific errors. </exception>
+        /// <exception cref="RequestFailedException">Thrown when the request does not reach the Relay Allocation Service.</exception>
+        /// <exception cref="ArgumentException">Thrown if the joinCode has the wrong format.</exception>
+        /// <exception cref="RelayServiceException">Thrown when the request successfully reach the Relay Allocation Service but results in an error.</exception>
+        /// <returns>True if starting the client was successful</returns>
+        internal static async Task<JoinAllocation> StartClientWithRelay(this NetworkManager networkManager, string joinCode)
+        {
+            await UnityServices.InitializeAsync();
+            if (!AuthenticationService.Instance.IsSignedIn)
+            {
+                await AuthenticationService.Instance.SignInAnonymouslyAsync();
+            }
+            var joinAllocation = await RelayService.Instance.JoinAllocationAsync(joinCode: joinCode);
+            GetUnityTransport(networkManager, k_DefaultConnectionType).SetRelayServerData(new RelayServerData(joinAllocation, k_DefaultConnectionType));
+            return networkManager.StartClient() ? joinAllocation : null;
+        }
+
+        private static async Task<(string, Allocation)> InitializeAndCreateAllocAsync(NetworkManager networkManager, int maxConnections, string connectionType)
+        {
+            await UnityServices.InitializeAsync();
+            if (!AuthenticationService.Instance.IsSignedIn)
+            {
+                await AuthenticationService.Instance.SignInAnonymouslyAsync();
+            }
+            Allocation allocation = await RelayService.Instance.CreateAllocationAsync(maxConnections);
+            GetUnityTransport(networkManager, connectionType).SetRelayServerData(new RelayServerData(allocation, connectionType));
+            var joinCode = await RelayService.Instance.GetJoinCodeAsync(allocation.AllocationId);
+            return (joinCode, allocation);
+        }
+
+        private static UnityTransport GetUnityTransport(NetworkManager networkManager, string connectionType)
+        {
+            if (!networkManager.TryGetComponent<UnityTransport>(out var transport))
+            {
+                transport = networkManager.gameObject.AddComponent<UnityTransport>();
+            }
+#if UTP_TRANSPORT_2_0_ABOVE
+            transport.UseWebSockets = connectionType.StartsWith("ws"); // Probably should be part of SetRelayServerData, but not possible at this point
+#endif
+            networkManager.NetworkConfig.NetworkTransport = transport; // Force using UnityTransport
+            return transport;
+        }
+    }
+}
+#endif

Editor/NetworkManagerRelayIntegration.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: 23b658b1c2e443109a8a131ef3632c9b
+timeCreated: 1698673251

Editor/NetworkObjectEditor.cs

@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using System.Linq;
 using UnityEditor;
 using UnityEngine;
 
@@ -49,6 +50,10 @@ namespace Unity.Netcode.Editor
             {
                 var guiEnabled = GUI.enabled;
                 GUI.enabled = false;
+                if (m_NetworkObject.NetworkManager.DistributedAuthorityMode)
+                {
+                    EditorGUILayout.PropertyField(serializedObject.FindProperty(nameof(NetworkObject.Ownership)));
+                }
                 EditorGUILayout.TextField(nameof(NetworkObject.GlobalObjectIdHash), m_NetworkObject.GlobalObjectIdHash.ToString());
                 EditorGUILayout.TextField(nameof(NetworkObject.NetworkObjectId), m_NetworkObject.NetworkObjectId.ToString());
                 EditorGUILayout.TextField(nameof(NetworkObject.OwnerClientId), m_NetworkObject.OwnerClientId.ToString());
@@ -138,4 +143,49 @@ namespace Unity.Netcode.Editor
             NetworkBehaviourEditor.CheckForNetworkObject(m_GameObject, true);
         }
     }
+
+
+    [CustomPropertyDrawer(typeof(NetworkObject.OwnershipStatus))]
+    public class NetworkObjectOwnership : PropertyDrawer
+    {
+        public override void OnGUI(Rect position, SerializedProperty property, GUIContent label)
+        {
+            label = EditorGUI.BeginProperty(position, label, property);
+            // Don't allow modification while in play mode
+            EditorGUI.BeginDisabledGroup(EditorApplication.isPlaying);
+
+            // This is a temporary work around due to EditorGUI.EnumFlagsField having a bug in how it displays mask values.
+            // For now, we will just display the flags as a toggle and handle the masking of the value ourselves.
+            EditorGUILayout.BeginHorizontal();
+            var names = System.Enum.GetNames(typeof(NetworkObject.OwnershipStatus)).ToList();
+            names.RemoveAt(0);
+            var value = property.enumValueFlag;
+            var compareValue = 0x01;
+            GUILayout.Label(label);
+            foreach (var name in names)
+            {
+                var isSet = (value & compareValue) > 0;
+                isSet = GUILayout.Toggle(isSet, name);
+                if (isSet)
+                {
+                    value |= compareValue;
+                }
+                else
+                {
+                    value &= ~compareValue;
+                }
+                compareValue = compareValue << 1;
+            }
+            property.enumValueFlag = value;
+            EditorGUILayout.EndHorizontal();
+
+            // The below can cause visual anomalies and/or throws an exception within the EditorGUI itself (index out of bounds of the array). and has
+            // The visual anomaly is when you select one field it is set in the drop down but then the flags selection in the popup menu selects more items
+            // even though if you exit the popup menu the flag setting is correct. 
+            //var ownership = (NetworkObject.OwnershipStatus)EditorGUI.EnumFlagsField(position, label, (NetworkObject.OwnershipStatus)property.enumValueFlag);
+            //property.enumValueFlag = (int)ownership;
+            EditorGUI.EndDisabledGroup();
+            EditorGUI.EndProperty();
+        }
+    }
 }

Editor/NetworkTransformEditor.cs

@@ -10,6 +10,7 @@ namespace Unity.Netcode.Editor
     [CustomEditor(typeof(NetworkTransform), true)]
     public class NetworkTransformEditor : UnityEditor.Editor
     {
+        private SerializedProperty m_UseUnreliableDeltas;
         private SerializedProperty m_SyncPositionXProperty;
         private SerializedProperty m_SyncPositionYProperty;
         private SerializedProperty m_SyncPositionZProperty;
@@ -39,6 +40,7 @@ namespace Unity.Netcode.Editor
         /// <inheritdoc/>
         public void OnEnable()
         {
+            m_UseUnreliableDeltas = serializedObject.FindProperty(nameof(NetworkTransform.UseUnreliableDeltas));
             m_SyncPositionXProperty = serializedObject.FindProperty(nameof(NetworkTransform.SyncPositionX));
             m_SyncPositionYProperty = serializedObject.FindProperty(nameof(NetworkTransform.SyncPositionY));
             m_SyncPositionZProperty = serializedObject.FindProperty(nameof(NetworkTransform.SyncPositionZ));
@@ -129,7 +131,9 @@ namespace Unity.Netcode.Editor
             EditorGUILayout.PropertyField(m_PositionThresholdProperty);
             EditorGUILayout.PropertyField(m_RotAngleThresholdProperty);
             EditorGUILayout.PropertyField(m_ScaleThresholdProperty);
-
+            EditorGUILayout.Space();
+            EditorGUILayout.LabelField("Delivery", EditorStyles.boldLabel);
+            EditorGUILayout.PropertyField(m_UseUnreliableDeltas);
             EditorGUILayout.Space();
             EditorGUILayout.LabelField("Configurations", EditorStyles.boldLabel);
             EditorGUILayout.PropertyField(m_InLocalSpaceProperty);

Editor/com.unity.netcode.editor.asmdef

@@ -3,11 +3,21 @@
     "rootNamespace": "Unity.Netcode.Editor",
     "references": [
         "Unity.Netcode.Runtime",
-        "Unity.Netcode.Components"
+        "Unity.Netcode.Components",
+        "Unity.Services.Relay",
+        "Unity.Networking.Transport",
+        "Unity.Services.Core",
+        "Unity.Services.Authentication"
     ],
     "includePlatforms": [
         "Editor"
     ],
+    "excludePlatforms": [],
+    "allowUnsafeCode": false,
+    "overrideReferences": false,
+    "precompiledReferences": [],
+    "autoReferenced": true,
+    "defineConstraints": [],
     "versionDefines": [
         {
             "name": "com.unity.multiplayer.tools",
@@ -33,6 +43,17 @@
             "name": "com.unity.modules.physics2d",
             "expression": "",
             "define": "COM_UNITY_MODULES_PHYSICS2D"
+        },
+        {
+            "name": "com.unity.services.relay",
+            "expression": "1.0",
+            "define": "RELAY_SDK_INSTALLED"
+        },
+        {
+            "name": "com.unity.transport",
+            "expression": "2.0",
+            "define": "UTP_TRANSPORT_2_0_ABOVE"
         }
-    ]
-}
+    ],
+    "noEngineReferences": false
+}

LICENSE.md

@@ -1,9 +1,7 @@
-MIT License
+Unity Companion License (UCL License)
 
-Copyright (c) 2021 Unity Technologies
+com.unity.netcode.gameobjects copyright ©  2021-2024 Unity Technologies
+Licensed under the Unity Companion License for Unity-dependent projects (see https://unity3d.com/legal/licenses/unity_companion_license).
+Unless expressly provided otherwise, the Software under this license is made available strictly on an “AS IS” BASIS WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED. Please review the license for details on these and other terms and conditions.
 
-Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
 
-The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Runtime/Configuration/NetworkConfig.cs

@@ -129,10 +129,10 @@ namespace Unity.Netcode
         public int LoadSceneTimeOut = 120;
 
         /// <summary>
-        /// The amount of time a message should be buffered if the asset or object needed to process it doesn't exist yet. If the asset is not added/object is not spawned within this time, it will be dropped.
+        /// The amount of time a message will be held (deferred) if the destination NetworkObject needed to process the message doesn't exist yet. If the NetworkObject is not spawned within this time period, all deferred messages for that NetworkObject will be dropped.
         /// </summary>
-        [Tooltip("The amount of time a message should be buffered if the asset or object needed to process it doesn't exist yet. If the asset is not added/object is not spawned within this time, it will be dropped")]
-        public float SpawnTimeout = 1f;
+        [Tooltip("The amount of time a message will be held (deferred) if the destination NetworkObject needed to process the message doesn't exist yet. If the NetworkObject is not spawned within this time period, all deferred messages for that NetworkObject will be dropped.")]
+        public float SpawnTimeout = 10f;
 
         /// <summary>
         /// Whether or not to enable network logs.
@@ -149,6 +149,15 @@ namespace Unity.Netcode
         /// </summary>
         public const int RttWindowSize = 64; // number of slots to use for RTT computations (max number of in-flight packets)
 
+        [Tooltip("Determines if the network session will run in client-server or distributed authority mode.")]
+        public SessionModeTypes SessionMode;
+
+        [HideInInspector]
+        public bool UseCMBService;
+
+        [Tooltip("When enabled (default), the player prefab will automatically be spawned (client-side) upon the client being approved and synchronized.")]
+        public bool AutoSpawnPlayerPrefabClientSide = true;
+
         /// <summary>
         /// Returns a base64 encoded version of the configuration
         /// </summary>

Runtime/Configuration/NetworkPrefabs.cs

@@ -30,6 +30,12 @@ namespace Unity.Netcode
         [NonSerialized]
         public Dictionary<uint, NetworkPrefab> NetworkPrefabOverrideLinks = new Dictionary<uint, NetworkPrefab>();
 
+        /// <summary>
+        /// This is used for the legacy way of spawning NetworkPrefabs with an override when manually instantiating and spawning.
+        /// To handle multiple source NetworkPrefab overrides that all point to the same target NetworkPrefab use
+        /// <see cref="NetworkSpawnManager.InstantiateAndSpawn(NetworkObject, ulong, bool, bool, bool, Vector3, Quaternion)"/>
+        /// or <see cref="NetworkObject.InstantiateAndSpawn(NetworkManager, ulong, bool, bool, bool, Vector3, Quaternion)"/>
+        /// </summary>
         [NonSerialized]
         public Dictionary<uint, uint> OverrideToNetworkPrefab = new Dictionary<uint, uint>();
 
@@ -234,7 +240,8 @@ namespace Unity.Netcode
         {
             for (int i = 0; i < m_Prefabs.Count; i++)
             {
-                if (m_Prefabs[i].Prefab == prefab)
+                // Check both values as Prefab and be different than SourcePrefabToOverride
+                if (m_Prefabs[i].Prefab == prefab || m_Prefabs[i].SourcePrefabToOverride == prefab)
                 {
                     return true;
                 }
@@ -262,7 +269,7 @@ namespace Unity.Netcode
         }
 
         /// <summary>
-        /// Configures <see cref="NetworkPrefabOverrideLinks"/> and <see cref="OverrideToNetworkPrefab"/> for the given <see cref="NetworkPrefab"/>
+        /// Configures <see cref="NetworkPrefabOverrideLinks"/> for the given <see cref="NetworkPrefab"/>
         /// </summary>
         private bool AddPrefabRegistration(NetworkPrefab networkPrefab)
         {
@@ -296,28 +303,16 @@ namespace Unity.Netcode
                 return true;
             }
 
-            // Make sure we don't have several overrides targeting the same prefab. Apparently we don't support that... shame.
-            if (OverrideToNetworkPrefab.ContainsKey(target))
-            {
-                var networkObject = networkPrefab.Prefab.GetComponent<NetworkObject>();
-
-                // This can happen if a user tries to make several GlobalObjectIdHash values point to the same target
-                Debug.LogError($"{nameof(NetworkPrefab)} (\"{networkObject.name}\") has a duplicate {nameof(NetworkObject.GlobalObjectIdHash)} target entry value of: {target}!");
-                return false;
-            }
-
             switch (networkPrefab.Override)
             {
                 case NetworkPrefabOverride.Prefab:
-                    {
-                        NetworkPrefabOverrideLinks.Add(source, networkPrefab);
-                        OverrideToNetworkPrefab.Add(target, source);
-                    }
-                    break;
                 case NetworkPrefabOverride.Hash:
                     {
                         NetworkPrefabOverrideLinks.Add(source, networkPrefab);
-                        OverrideToNetworkPrefab.Add(target, source);
+                        if (!OverrideToNetworkPrefab.ContainsKey(target))
+                        {
+                            OverrideToNetworkPrefab.Add(target, source);
+                        }
                     }
                     break;
             }

Runtime/Connection/NetworkClient.cs

@@ -1,7 +1,15 @@
 using System.Collections.Generic;
+using UnityEngine;
 
 namespace Unity.Netcode
 {
+
+    public enum SessionModeTypes
+    {
+        ClientServer,
+        DistributedAuthority
+    }
+
     /// <summary>
     /// A NetworkClient
     /// </summary>
@@ -33,6 +41,15 @@ namespace Unity.Netcode
         /// </summary>
         internal bool IsApproved { get; set; }
 
+        public SessionModeTypes SessionModeType { get; internal set; }
+
+        public bool DAHost { get; internal set; }
+
+        /// <summary>
+        /// Is true when the client has been assigned session ownership in distributed authority mode
+        /// </summary>
+        public bool IsSessionOwner { get; internal set; }
+
         /// <summary>
         /// The ClientId of the NetworkClient
         /// </summary>
@@ -50,21 +67,54 @@ namespace Unity.Netcode
 
         internal NetworkSpawnManager SpawnManager { get; private set; }
 
-        internal void SetRole(bool isServer, bool isClient, NetworkManager networkManager = null)
+        internal bool SetRole(bool isServer, bool isClient, NetworkManager networkManager = null)
         {
+            ResetClient(isServer, isClient);
+
             IsServer = isServer;
             IsClient = isClient;
-            if (!IsServer && !isClient)
+
+            if (networkManager != null)
+            {
+                SpawnManager = networkManager.SpawnManager;
+                SessionModeType = networkManager.NetworkConfig.SessionMode;
+
+                if (SessionModeType == SessionModeTypes.DistributedAuthority)
+                {
+                    DAHost = IsClient && IsServer;
+
+                    // DANGO-TODO: We might allow a dedicated mock CMB server, but for now do not allow this
+                    if (!IsClient && IsServer)
+                    {
+                        Debug.LogError("You cannot start NetworkManager as a server when operating in distributed authority mode!");
+                        return false;
+                    }
+
+                    if (DAHost && networkManager.CMBServiceConnection)
+                    {
+                        Debug.LogError("You cannot start a host when connecting to a distributed authority CMB Service!");
+                        return false;
+                    }
+                }
+            }
+            return true;
+        }
+
+        /// <summary>
+        /// Only to be invoked when setting the role.
+        /// This resets the current NetworkClient's properties.
+        /// </summary>
+        private void ResetClient(bool isServer, bool isClient)
+        {
+            // If we are niether client nor server, then reset properties (i.e. client has no role)
+            if (!IsServer && !IsClient)
             {
                 PlayerObject = null;
                 ClientId = 0;
                 IsConnected = false;
                 IsApproved = false;
-            }
-
-            if (networkManager != null)
-            {
-                SpawnManager = networkManager.SpawnManager;
+                SpawnManager = null;
+                DAHost = false;
             }
         }
 

Runtime/Connection/NetworkConnectionManager.cs

@@ -1,15 +1,47 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
+using System.Linq;
 using System.Runtime.CompilerServices;
 using Unity.Collections;
 using Unity.Collections.LowLevel.Unsafe;
 using Unity.Profiling;
 using UnityEngine;
-using Object = UnityEngine.Object;
 
 namespace Unity.Netcode
 {
+
+    public enum ConnectionEvent
+    {
+        ClientConnected,
+        PeerConnected,
+        ClientDisconnected,
+        PeerDisconnected
+    }
+
+    public struct ConnectionEventData
+    {
+        public ConnectionEvent EventType;
+
+        /// <summary>
+        /// The client ID for the client that just connected
+        /// For the <see cref="ConnectionEvent.ClientConnected"/> and <see cref="ConnectionEvent.ClientDisconnected"/>
+        /// events on the client side, this will be LocalClientId.
+        /// On the server side, this will be the ID of the client that just connected.
+        ///
+        /// For the <see cref="ConnectionEvent.PeerConnected"/> and <see cref="ConnectionEvent.PeerDisconnected"/>
+        /// events on the client side, this will be the client ID assigned by the server to the remote peer.
+        /// </summary>
+        public ulong ClientId;
+
+        /// <summary>
+        /// This is only populated in <see cref="ConnectionEvent.ClientConnected"/> on the client side, and
+        /// contains the list of other peers who were present before you connected. In all other situations,
+        /// this array will be uninitialized.
+        /// </summary>
+        public NativeArray<ulong> PeerClientIds;
+    }
+
     /// <summary>
     /// The NGO connection manager handles:
     /// - Client Connections
@@ -42,7 +74,105 @@ namespace Unity.Netcode
         /// </summary>
         public event Action<ulong> OnClientDisconnectCallback = null;
 
-        internal void InvokeOnClientConnectedCallback(ulong clientId) => OnClientConnectedCallback?.Invoke(clientId);
+        /// <summary>
+        /// The callback to invoke once a peer connects. This callback is only ran on the server and on the local client that connects.
+        /// </summary>
+        public event Action<NetworkManager, ConnectionEventData> OnConnectionEvent = null;
+
+
+        internal void InvokeOnClientConnectedCallback(ulong clientId)
+        {
+            try
+            {
+                OnClientConnectedCallback?.Invoke(clientId);
+            }
+            catch (Exception exception)
+            {
+                Debug.LogException(exception);
+            }
+
+            if (!NetworkManager.IsServer)
+            {
+                var peerClientIds = new NativeArray<ulong>(Math.Max(NetworkManager.ConnectedClientsIds.Count - 1, 0), Allocator.Temp);
+                // `using var peerClientIds` or `using(peerClientIds)` renders it immutable...
+                using var sentinel = peerClientIds;
+
+                var idx = 0;
+                foreach (var peerId in NetworkManager.ConnectedClientsIds)
+                {
+                    if (peerId == NetworkManager.LocalClientId)
+                    {
+                        continue;
+                    }
+
+                    peerClientIds[idx] = peerId;
+                    ++idx;
+                }
+
+                try
+                {
+                    OnConnectionEvent?.Invoke(NetworkManager, new ConnectionEventData { ClientId = NetworkManager.LocalClientId, EventType = ConnectionEvent.ClientConnected, PeerClientIds = peerClientIds });
+                }
+                catch (Exception exception)
+                {
+                    Debug.LogException(exception);
+                }
+            }
+            else
+            {
+                try
+                {
+                    OnConnectionEvent?.Invoke(NetworkManager, new ConnectionEventData { ClientId = clientId, EventType = ConnectionEvent.ClientConnected });
+                }
+                catch (Exception exception)
+                {
+                    Debug.LogException(exception);
+                }
+            }
+        }
+
+        internal void InvokeOnClientDisconnectCallback(ulong clientId)
+        {
+            try
+            {
+                OnClientDisconnectCallback?.Invoke(clientId);
+            }
+            catch (Exception exception)
+            {
+                Debug.LogException(exception);
+            }
+            try
+            {
+                OnConnectionEvent?.Invoke(NetworkManager, new ConnectionEventData { ClientId = clientId, EventType = ConnectionEvent.ClientDisconnected });
+            }
+            catch (Exception exception)
+            {
+                Debug.LogException(exception);
+            }
+        }
+
+        internal void InvokeOnPeerConnectedCallback(ulong clientId)
+        {
+            try
+            {
+                OnConnectionEvent?.Invoke(NetworkManager, new ConnectionEventData { ClientId = clientId, EventType = ConnectionEvent.PeerConnected });
+            }
+            catch (Exception exception)
+            {
+                Debug.LogException(exception);
+            }
+        }
+        internal void InvokeOnPeerDisconnectedCallback(ulong clientId)
+        {
+            try
+            {
+                OnConnectionEvent?.Invoke(NetworkManager, new ConnectionEventData { ClientId = clientId, EventType = ConnectionEvent.PeerDisconnected });
+            }
+            catch (Exception exception)
+            {
+                Debug.LogException(exception);
+            }
+        }
 
         /// <summary>
         /// The callback to invoke if the <see cref="NetworkTransport"/> fails.
@@ -217,7 +347,7 @@ namespace Unity.Netcode
             // When this happens, the client will not have an entry within the m_TransportIdToClientIdMap or m_ClientIdToTransportIdMap lookup tables so we exit early and just return 0 to be used for the disconnect event.
             if (!LocalClient.IsServer && !TransportIdToClientIdMap.ContainsKey(transportId))
             {
-                return 0;
+                return NetworkManager.LocalClientId;
             }
 
             var clientId = TransportIdToClientId(transportId);
@@ -236,6 +366,10 @@ namespace Unity.Netcode
             {
                 networkEvent = NetworkManager.NetworkConfig.NetworkTransport.PollEvent(out ulong transportClientId, out ArraySegment<byte> payload, out float receiveTime);
                 HandleNetworkEvent(networkEvent, transportClientId, payload, receiveTime);
+                if (networkEvent == NetworkEvent.Disconnect || networkEvent == NetworkEvent.TransportFailure)
+                {
+                    break;
+                }
                 // Only do another iteration if: there are no more messages AND (there is no limit to max events or we have processed less than the maximum)
             } while (NetworkManager.IsListening && networkEvent != NetworkEvent.Nothing);
 
@@ -300,16 +434,17 @@ namespace Unity.Netcode
             {
                 if (NetworkLog.CurrentLogLevel <= LogLevel.Developer)
                 {
-                    NetworkLog.LogInfo("Client Connected");
+                    var hostServer = NetworkManager.IsHost ? "Host" : "Server";
+                    NetworkLog.LogInfo($"[{hostServer}-Side] Transport connection established with pending Client-{clientId}.");
                 }
-
                 AddPendingClient(clientId);
             }
             else
             {
                 if (NetworkLog.CurrentLogLevel <= LogLevel.Developer)
                 {
-                    NetworkLog.LogInfo("Connected");
+                    var serverOrService = NetworkManager.DistributedAuthorityMode ? NetworkManager.CMBServiceConnection ? "service" : "DAHost" : "server";
+                    NetworkLog.LogInfo($"[Approval Pending][Client] Transport connection with {serverOrService} established! Awaiting connection approval...");
                 }
 
                 SendConnectionRequest();
@@ -346,31 +481,38 @@ namespace Unity.Netcode
             s_TransportDisconnect.Begin();
 #endif
             var clientId = TransportIdCleanUp(transportClientId);
-
             if (NetworkLog.CurrentLogLevel <= LogLevel.Developer)
             {
                 NetworkLog.LogInfo($"Disconnect Event From {clientId}");
             }
 
+            // If we are a client and we have gotten the ServerClientId back, then use our assigned local id as the client that was
+            // disconnected (either the user disconnected or the server disconnected, but the client that disconnected is the LocalClientId)
+            if (!NetworkManager.IsServer && clientId == NetworkManager.ServerClientId)
+            {
+                clientId = NetworkManager.LocalClientId;
+            }
+
             // Process the incoming message queue so that we get everything from the server disconnecting us or, if we are the server, so we got everything from that client.
             MessageManager.ProcessIncomingMessageQueue();
 
-            try
+            InvokeOnClientDisconnectCallback(clientId);
+
+            if (LocalClient.IsHost)
             {
-                OnClientDisconnectCallback?.Invoke(clientId);
-            }
-            catch (Exception exception)
-            {
-                Debug.LogException(exception);
+                InvokeOnPeerDisconnectedCallback(clientId);
             }
 
             if (LocalClient.IsServer)
             {
                 OnClientDisconnectFromServer(clientId);
             }
-            else
+            else // As long as we are not in the middle of a shutdown
+            if (!NetworkManager.ShutdownInProgress)
             {
-                // We must pass true here and not process any sends messages as we are no longer connected and thus there is no one to send any messages to and this will cause an exception within UnityTransport as the client ID is no longer valid.
+                // We must pass true here and not process any sends messages as we are no longer connected.
+                // Otherwise, attempting to process messages here can cause an exception within UnityTransport
+                // as the client ID is no longer valid.
                 NetworkManager.Shutdown(true);
             }
 #if DEVELOPMENT_BUILD || UNITY_EDITOR
@@ -409,6 +551,10 @@ namespace Unity.Netcode
         {
             var message = new ConnectionRequestMessage
             {
+                CMBServiceConnection = NetworkManager.CMBServiceConnection,
+                TickRate = NetworkManager.NetworkConfig.TickRate,
+                EnableSceneManagement = NetworkManager.NetworkConfig.EnableSceneManagement,
+
                 // Since only a remote client will send a connection request, we should always force the rebuilding of the NetworkConfig hash value
                 ConfigHash = NetworkManager.NetworkConfig.GetConfig(false),
                 ShouldSendConnectionData = NetworkManager.NetworkConfig.ConnectionApproval,
@@ -564,6 +710,12 @@ namespace Unity.Netcode
             }
         }
 
+        /// <summary>
+        /// Adding this because message hooks cannot happen fast enough under certain scenarios
+        /// where the message is sent and responded to before the hook is in place.
+        /// </summary>
+        internal bool MockSkippingApproval;
+
         /// <summary>
         /// Server Side: Handles the approval of a client
         /// </summary>
@@ -575,12 +727,15 @@ namespace Unity.Netcode
             LocalClient.IsApproved = response.Approved;
             if (response.Approved)
             {
+                if (NetworkLog.CurrentLogLevel <= LogLevel.Developer)
+                {
+                    NetworkLog.LogInfo($"[Server-Side] Pending Client-{ownerClientId} connection approved!");
+                }
                 // The client was approved, stop the server-side approval time out coroutine
                 RemovePendingClient(ownerClientId);
 
                 var client = AddClient(ownerClientId);
-
-                if (response.CreatePlayerObject)
+                if (!NetworkManager.DistributedAuthorityMode && response.CreatePlayerObject && NetworkManager.NetworkConfig.PlayerPrefab != null)
                 {
                     var prefabNetworkObject = NetworkManager.NetworkConfig.PlayerPrefab.GetComponent<NetworkObject>();
                     var playerPrefabHash = response.PlayerPrefabHash ?? prefabNetworkObject.GlobalObjectIdHash;
@@ -595,6 +750,7 @@ namespace Unity.Netcode
                         HasTransform = prefabNetworkObject.SynchronizeTransform,
                         Hash = playerPrefabHash,
                         TargetClientId = ownerClientId,
+                        DontDestroyWithOwner = prefabNetworkObject.DontDestroyWithOwner,
                         Transform = new NetworkObject.SceneObject.TransformData
                         {
                             Position = response.Position.GetValueOrDefault(),
@@ -623,8 +779,18 @@ namespace Unity.Netcode
                     var message = new ConnectionApprovedMessage
                     {
                         OwnerClientId = ownerClientId,
-                        NetworkTick = NetworkManager.LocalTime.Tick
+                        NetworkTick = NetworkManager.LocalTime.Tick,
+                        IsDistributedAuthority = NetworkManager.DistributedAuthorityMode,
+                        ConnectedClientIds = new NativeArray<ulong>(ConnectedClientIds.Count, Allocator.Temp)
                     };
+
+                    var i = 0;
+                    foreach (var clientId in ConnectedClientIds)
+                    {
+                        message.ConnectedClientIds[i] = clientId;
+                        ++i;
+                    }
+
                     if (!NetworkManager.NetworkConfig.EnableSceneManagement)
                     {
                         // Update the observed spawned NetworkObjects for the newly connected player when scene management is disabled
@@ -648,19 +814,43 @@ namespace Unity.Netcode
                             };
                         }
                     }
-
-                    SendMessage(ref message, NetworkDelivery.ReliableFragmentedSequenced, ownerClientId);
+                    if (!MockSkippingApproval)
+                    {
+                        SendMessage(ref message, NetworkDelivery.ReliableFragmentedSequenced, ownerClientId);
+                    }
+                    else
+                    {
+                        NetworkLog.LogInfo("Mocking server not responding with connection approved...");
+                    }
                     message.MessageVersions.Dispose();
+                    message.ConnectedClientIds.Dispose();
+                    if (MockSkippingApproval)
+                    {
+                        return;
+                    }
 
                     // If scene management is disabled, then we are done and notify the local host-server the client is connected
                     if (!NetworkManager.NetworkConfig.EnableSceneManagement)
                     {
                         NetworkManager.ConnectedClients[ownerClientId].IsConnected = true;
                         InvokeOnClientConnectedCallback(ownerClientId);
+                        if (LocalClient.IsHost)
+                        {
+                            InvokeOnPeerConnectedCallback(ownerClientId);
+                        }
+                        NetworkManager.SpawnManager.DistributeNetworkObjects(ownerClientId);
+
                     }
                     else // Otherwise, let NetworkSceneManager handle the initial scene and NetworkObject synchronization
                     {
-                        NetworkManager.SceneManager.SynchronizeNetworkObjects(ownerClientId);
+                        if (NetworkManager.DistributedAuthorityMode && NetworkManager.LocalClient.IsSessionOwner)
+                        {
+                            NetworkManager.SceneManager.SynchronizeNetworkObjects(ownerClientId);
+                        }
+                        else if (!NetworkManager.DistributedAuthorityMode)
+                        {
+                            NetworkManager.SceneManager.SynchronizeNetworkObjects(ownerClientId);
+                        }
                     }
                 }
                 else // Server just adds itself as an observer to all spawned NetworkObjects
@@ -668,6 +858,17 @@ namespace Unity.Netcode
                     LocalClient = client;
                     NetworkManager.SpawnManager.UpdateObservedNetworkObjects(ownerClientId);
                     LocalClient.IsConnected = true;
+                    // If running mock service, then set the instance as the default session owner
+                    if (NetworkManager.DistributedAuthorityMode && NetworkManager.DAHost)
+                    {
+                        NetworkManager.SetSessionOwner(NetworkManager.LocalClientId);
+                        NetworkManager.SceneManager.InitializeScenesLoaded();
+                    }
+
+                    if (NetworkManager.DistributedAuthorityMode && NetworkManager.AutoSpawnPlayerPrefabClientSide)
+                    {
+                        CreateAndSpawnPlayer(ownerClientId);
+                    }
                 }
 
                 if (!response.CreatePlayerObject || (response.PlayerPrefabHash == null && NetworkManager.NetworkConfig.PlayerPrefab == null))
@@ -675,6 +876,11 @@ namespace Unity.Netcode
                     return;
                 }
 
+                // Players are always spawned by their respective client, exit early. (DAHost mode anyway, CMB Service will never spawn player prefab)
+                if (NetworkManager.DistributedAuthorityMode)
+                {
+                    return;
+                }
                 // Separating this into a contained function call for potential further future separation of when this notification is sent.
                 ApprovedPlayerSpawn(ownerClientId, response.PlayerPrefabHash ?? NetworkManager.NetworkConfig.PlayerPrefab.GetComponent<NetworkObject>().GlobalObjectIdHash);
             }
@@ -689,11 +895,28 @@ namespace Unity.Netcode
                     SendMessage(ref disconnectReason, NetworkDelivery.Reliable, ownerClientId);
                     MessageManager.ProcessSendQueues();
                 }
-
                 DisconnectRemoteClient(ownerClientId);
             }
         }
 
+        /// <summary>
+        /// Client-Side Spawning in distributed authority mode uses this to spawn the player.
+        /// </summary>
+        internal void CreateAndSpawnPlayer(ulong ownerId, Vector3 position = default, Quaternion rotation = default)
+        {
+            if (NetworkManager.DistributedAuthorityMode && NetworkManager.AutoSpawnPlayerPrefabClientSide)
+            {
+                var playerPrefab = NetworkManager.FetchLocalPlayerPrefabToSpawn();
+                if (playerPrefab != null)
+                {
+                    var globalObjectIdHash = playerPrefab.GetComponent<NetworkObject>().GlobalObjectIdHash;
+                    var networkObject = NetworkManager.SpawnManager.GetNetworkObjectToSpawn(globalObjectIdHash, ownerId, position, rotation);
+                    networkObject.IsSceneObject = false;
+                    networkObject.SpawnAsPlayerObject(ownerId, networkObject.DestroyWithScene);
+                }
+            }
+        }
+
         /// <summary>
         /// Spawns the newly approved player
         /// </summary>
@@ -713,8 +936,10 @@ namespace Unity.Netcode
 
                 var message = new CreateObjectMessage
                 {
-                    ObjectInfo = ConnectedClients[clientId].PlayerObject.GetMessageSceneObject(clientPair.Key)
+                    ObjectInfo = ConnectedClients[clientId].PlayerObject.GetMessageSceneObject(clientPair.Key),
+                    IncludesSerializedObject = true,
                 };
+
                 message.ObjectInfo.Hash = playerPrefabHash;
                 message.ObjectInfo.IsSceneObject = false;
                 message.ObjectInfo.HasParent = false;
@@ -732,18 +957,92 @@ namespace Unity.Netcode
         /// </summary>
         internal NetworkClient AddClient(ulong clientId)
         {
+            if (ConnectedClients.ContainsKey(clientId) && ConnectedClientIds.Contains(clientId) && ConnectedClientsList.Contains(ConnectedClients[clientId]))
+            {
+                return ConnectedClients[clientId];
+            }
+
             var networkClient = LocalClient;
 
-            networkClient = new NetworkClient();
+            // If this is not the local client then create a new one
+            if (clientId != NetworkManager.LocalClientId)
+            {
+                networkClient = new NetworkClient();
+            }
             networkClient.SetRole(clientId == NetworkManager.ServerClientId, isClient: true, NetworkManager);
             networkClient.ClientId = clientId;
+            if (!ConnectedClients.ContainsKey(clientId))
+            {
+                ConnectedClients.Add(clientId, networkClient);
+            }
+            if (!ConnectedClientsList.Contains(networkClient))
+            {
+                ConnectedClientsList.Add(networkClient);
+            }
+
+            if (NetworkManager.LocalClientId != clientId)
+            {
+                if ((!NetworkManager.DistributedAuthorityMode && NetworkManager.IsServer) ||
+                    (NetworkManager.DistributedAuthorityMode && NetworkManager.NetworkConfig.EnableSceneManagement && NetworkManager.DAHost && NetworkManager.LocalClient.IsSessionOwner))
+                {
+                    var message = new ClientConnectedMessage { ClientId = clientId };
+                    NetworkManager.MessageManager.SendMessage(ref message, NetworkDelivery.ReliableSequenced, ConnectedClientIds.Where((c) => c != NetworkManager.LocalClientId).ToArray());
+                }
+                else if (NetworkManager.DistributedAuthorityMode && NetworkManager.NetworkConfig.EnableSceneManagement && NetworkManager.DAHost && !NetworkManager.LocalClient.IsSessionOwner)
+                {
+                    var message = new ClientConnectedMessage
+                    {
+                        ShouldSynchronize = true,
+                        ClientId = clientId
+                    };
+                    NetworkManager.MessageManager.SendMessage(ref message, NetworkDelivery.ReliableSequenced, NetworkManager.CurrentSessionOwner);
+                }
+            }
+            if (!ConnectedClientIds.Contains(clientId))
+            {
+                ConnectedClientIds.Add(clientId);
+            }
+
+            foreach (var networkObject in NetworkManager.SpawnManager.SpawnedObjectsList)
+            {
+                if (networkObject.SpawnWithObservers)
+                {
+                    networkObject.Observers.Add(clientId);
+                }
+            }
 
-            ConnectedClients.Add(clientId, networkClient);
-            ConnectedClientsList.Add(networkClient);
-            ConnectedClientIds.Add(clientId);
             return networkClient;
         }
 
+        /// <summary>
+        /// Invoked on clients when another client disconnects
+        /// </summary>
+        /// <param name="clientId">the client identifier to remove</param>
+        internal void RemoveClient(ulong clientId)
+        {
+            if (ConnectedClientIds.Contains(clientId))
+            {
+                ConnectedClientIds.Remove(clientId);
+            }
+            if (ConnectedClients.ContainsKey(clientId))
+            {
+                ConnectedClientsList.Remove(ConnectedClients[clientId]);
+            }
+
+            ConnectedClients.Remove(clientId);
+
+            foreach (var networkObject in NetworkManager.SpawnManager.SpawnedObjectsList)
+            {
+                networkObject.Observers.Remove(clientId);
+            }
+        }
+
+        /// <summary>
+        /// DANGO-TODO: Until we have the CMB Server end-to-end with all features verified working via integration tests,
+        /// I am keeping this debug toggle available. (NSS)
+        /// </summary>
+        internal bool EnableDistributeLogging;
+
         /// <summary>
         /// Server-Side:
         /// Invoked when a client is disconnected from a server-host
@@ -757,6 +1056,7 @@ namespace Unity.Netcode
 
             // If we are shutting down and this is the server or host disconnecting, then ignore
             // clean up as everything that needs to be destroyed will be during shutdown.
+
             if (NetworkManager.ShutdownInProgress && clientId == NetworkManager.ServerClientId)
             {
                 return;
@@ -769,25 +1069,55 @@ namespace Unity.Netcode
                 {
                     if (!playerObject.DontDestroyWithOwner)
                     {
-                        if (NetworkManager.PrefabHandler.ContainsHandler(ConnectedClients[clientId].PlayerObject.GlobalObjectIdHash))
+                        // DANGO-TODO: This is something that would be best for CMB Service to handle as it is part of the disconnection process
+                        // If a player NetworkObject is being despawned, make sure to remove all children if they are marked to not be destroyed
+                        // with the owner.
+                        if (NetworkManager.DistributedAuthorityMode && NetworkManager.DAHost)
                         {
-                            NetworkManager.PrefabHandler.HandleNetworkPrefabDestroy(ConnectedClients[clientId].PlayerObject);
+                            // Remove any children from the player object if they are not going to be destroyed with the owner
+                            var childNetworkObjects = playerObject.GetComponentsInChildren<NetworkObject>();
+                            foreach (var child in childNetworkObjects)
+                            {
+                                // TODO: We have always just removed all children, but we might think about changing this to preserve the nested child
+                                // hierarchy.
+                                if (child.DontDestroyWithOwner && child.transform.transform.parent != null)
+                                {
+                                    // If we are here, then we are running in DAHost mode and have the authority to remove the child from its parent
+                                    child.AuthorityAppliedParenting = true;
+                                    child.TryRemoveParentCachedWorldPositionStays();
+                                }
+                            }
+                        }
+
+                        if (NetworkManager.PrefabHandler.ContainsHandler(playerObject.GlobalObjectIdHash))
+                        {
+                            if (NetworkManager.DAHost && NetworkManager.DistributedAuthorityMode)
+                            {
+                                NetworkManager.SpawnManager.DespawnObject(playerObject, true, NetworkManager.DistributedAuthorityMode);
+                            }
+                            else
+                            {
+                                NetworkManager.PrefabHandler.HandleNetworkPrefabDestroy(playerObject);
+                            }
                         }
                         else if (playerObject.IsSpawned)
                         {
                             // Call despawn to assure NetworkBehaviour.OnNetworkDespawn is invoked on the server-side (when the client side disconnected).
                             // This prevents the issue (when just destroying the GameObject) where any NetworkBehaviour component(s) destroyed before the NetworkObject would not have OnNetworkDespawn invoked.
-                            NetworkManager.SpawnManager.DespawnObject(playerObject, true);
+                            NetworkManager.SpawnManager.DespawnObject(playerObject, true, NetworkManager.DistributedAuthorityMode);
                         }
                     }
-                    else
+                    else if (!NetworkManager.ShutdownInProgress)
                     {
-                        playerObject.RemoveOwnership();
+                        if (!NetworkManager.ShutdownInProgress)
+                        {
+                            playerObject.RemoveOwnership();
+                        }
                     }
                 }
 
                 // Get the NetworkObjects owned by the disconnected client
-                var clientOwnedObjects = NetworkManager.SpawnManager.GetClientOwnedObjects(clientId);
+                var clientOwnedObjects = NetworkManager.SpawnManager.SpawnedObjectsList.Where((c) => c.OwnerClientId == clientId).ToList();
                 if (clientOwnedObjects == null)
                 {
                     // This could happen if a client is never assigned a player object and is disconnected
@@ -799,7 +1129,10 @@ namespace Unity.Netcode
                 }
                 else
                 {
-                    // Handle changing ownership and prefab handlers                    
+                    // Handle changing ownership and prefab handlers
+                    var clientCounter = 0;
+                    var predictedClientCount = ConnectedClientsList.Count - 1;
+                    var remainingClients = NetworkManager.DistributedAuthorityMode ? ConnectedClientsList.Where((c) => c.ClientId != clientId).ToList() : null;
                     for (int i = clientOwnedObjects.Count - 1; i >= 0; i--)
                     {
                         var ownedObject = clientOwnedObjects[i];
@@ -809,16 +1142,72 @@ namespace Unity.Netcode
                             {
                                 if (NetworkManager.PrefabHandler.ContainsHandler(clientOwnedObjects[i].GlobalObjectIdHash))
                                 {
+                                    NetworkManager.SpawnManager.DespawnObject(ownedObject, true, true);
                                     NetworkManager.PrefabHandler.HandleNetworkPrefabDestroy(clientOwnedObjects[i]);
                                 }
                                 else
                                 {
-                                    Object.Destroy(ownedObject.gameObject);
+                                    NetworkManager.SpawnManager.DespawnObject(ownedObject, true, true);
                                 }
                             }
-                            else
+                            else if (!NetworkManager.ShutdownInProgress)
                             {
-                                ownedObject.RemoveOwnership();
+                                // NOTE: All of the below code only handles ownership transfer.
+                                // For client-server, we just remove the ownership.
+                                // For distributed authority, we need to change ownership based on parenting
+                                if (NetworkManager.DistributedAuthorityMode)
+                                {
+                                    // Only NetworkObjects that have the OwnershipStatus.Distributable flag set and no parent
+                                    // (ownership is transferred to all children) will have their ownership redistributed.
+                                    if (ownedObject.IsOwnershipDistributable && ownedObject.GetCachedParent() == null)
+                                    {
+                                        if (ownedObject.IsOwnershipLocked)
+                                        {
+                                            ownedObject.SetOwnershipLock(false);
+                                        }
+
+                                        // DANGO-TODO: We will want to match how the CMB service handles this. For now, we just try to evenly distribute
+                                        // ownership.
+                                        var targetOwner = NetworkManager.ServerClientId;
+                                        if (predictedClientCount > 1)
+                                        {
+                                            clientCounter++;
+                                            clientCounter = clientCounter % predictedClientCount;
+                                            targetOwner = remainingClients[clientCounter].ClientId;
+                                        }
+                                        if (EnableDistributeLogging)
+                                        {
+                                            Debug.Log($"[Disconnected][Client-{clientId}][NetworkObjectId-{ownedObject.NetworkObjectId} Distributed to Client-{targetOwner}");
+                                        }
+                                        NetworkManager.SpawnManager.ChangeOwnership(ownedObject, targetOwner, true);
+                                        // DANGO-TODO: Should we try handling inactive NetworkObjects?
+                                        // Ownership gets passed down to all children
+                                        var childNetworkObjects = ownedObject.GetComponentsInChildren<NetworkObject>();
+                                        foreach (var childObject in childNetworkObjects)
+                                        {
+                                            // We already changed ownership for this
+                                            if (childObject == ownedObject)
+                                            {
+                                                continue;
+                                            }
+                                            // If the client owner disconnected, it is ok to unlock this at this point in time.
+                                            if (childObject.IsOwnershipLocked)
+                                            {
+                                                childObject.SetOwnershipLock(false);
+                                            }
+
+                                            NetworkManager.SpawnManager.ChangeOwnership(childObject, targetOwner, true);
+                                            if (EnableDistributeLogging)
+                                            {
+                                                Debug.Log($"[Disconnected][Client-{clientId}][Child of {ownedObject.NetworkObjectId}][NetworkObjectId-{ownedObject.NetworkObjectId} Distributed to Client-{targetOwner}");
+                                            }
+                                        }
+                                    }
+                                }
+                                else
+                                {
+                                    ownedObject.RemoveOwnership();
+                                }
                             }
                         }
                     }
@@ -837,6 +1226,39 @@ namespace Unity.Netcode
                 }
 
                 ConnectedClientIds.Remove(clientId);
+                var message = new ClientDisconnectedMessage { ClientId = clientId };
+                MessageManager?.SendMessage(ref message, NetworkDelivery.ReliableFragmentedSequenced, ConnectedClientIds);
+
+                if (NetworkManager.DistributedAuthorityMode && !NetworkManager.ShutdownInProgress && NetworkManager.IsListening)
+                {
+                    var newSessionOwner = NetworkManager.LocalClientId;
+                    if (ConnectedClientIds.Count > 1)
+                    {
+                        var lowestRTT = ulong.MaxValue;
+                        var unityTransport = NetworkManager.NetworkConfig.NetworkTransport as Transports.UTP.UnityTransport;
+
+                        foreach (var identifier in ConnectedClientIds)
+                        {
+                            if (identifier == NetworkManager.LocalClientId)
+                            {
+                                continue;
+                            }
+                            var rtt = unityTransport.GetCurrentRtt(identifier);
+                            if (rtt < lowestRTT)
+                            {
+                                newSessionOwner = identifier;
+                                lowestRTT = rtt;
+                            }
+                        }
+                    }
+
+                    var sessionOwnerMessage = new SessionOwnerMessage()
+                    {
+                        SessionOwner = newSessionOwner,
+                    };
+                    MessageManager?.SendMessage(ref sessionOwnerMessage, NetworkDelivery.ReliableFragmentedSequenced, ConnectedClientIds);
+                    NetworkManager.SetSessionOwner(newSessionOwner);
+                }
             }
 
             // If the client ID transport map exists
@@ -845,13 +1267,11 @@ namespace Unity.Netcode
                 var transportId = ClientIdToTransportId(clientId);
                 NetworkManager.NetworkConfig.NetworkTransport.DisconnectRemoteClient(transportId);
 
-                try
+                InvokeOnClientDisconnectCallback(clientId);
+
+                if (LocalClient.IsHost)
                 {
-                    OnClientDisconnectCallback?.Invoke(clientId);
-                }
-                catch (Exception exception)
-                {
-                    Debug.LogException(exception);
+                    InvokeOnPeerDisconnectedCallback(clientId);
                 }
 
                 // Clean up the transport to client (and vice versa) mappings
@@ -889,6 +1309,12 @@ namespace Unity.Netcode
                 throw new NotServerException($"Only server can disconnect remote clients. Please use `{nameof(Shutdown)}()` instead.");
             }
 
+            if (clientId == NetworkManager.ServerClientId)
+            {
+                Debug.LogWarning($"Disconnecting the local server-host client is not allowed. Use NetworkManager.Shutdown instead.");
+                return;
+            }
+
             if (!string.IsNullOrEmpty(reason))
             {
                 var disconnectReason = new DisconnectReasonMessage
@@ -933,13 +1359,8 @@ namespace Unity.Netcode
         /// </summary>
         internal void Shutdown()
         {
-            LocalClient.IsApproved = false;
-            LocalClient.IsConnected = false;
             if (LocalClient.IsServer)
             {
-                // make sure all messages are flushed before transport disconnect clients
-                MessageManager?.ProcessSendQueues();
-
                 // Build a list of all client ids to be disconnected
                 var disconnectedIds = new HashSet<ulong>();
 
@@ -975,9 +1396,15 @@ namespace Unity.Netcode
                 {
                     DisconnectRemoteClient(clientId);
                 }
+
+                // make sure all messages are flushed before transport disconnects clients
+                MessageManager?.ProcessSendQueues();
             }
             else if (NetworkManager != null && NetworkManager.IsListening && LocalClient.IsClient)
             {
+                // make sure all messages are flushed before disconnecting
+                MessageManager?.ProcessSendQueues();
+
                 // Client only, send disconnect and if transport throws and exception, log the exception and continue the shutdown sequence (or forever be shutting down)
                 try
                 {
@@ -989,6 +1416,12 @@ namespace Unity.Netcode
                 }
             }
 
+            LocalClient.IsApproved = false;
+            LocalClient.IsConnected = false;
+            ConnectedClients.Clear();
+            ConnectedClientIds.Clear();
+            ConnectedClientsList.Clear();
+
             if (NetworkManager != null && NetworkManager.NetworkConfig?.NetworkTransport != null)
             {
                 NetworkManager.NetworkConfig.NetworkTransport.OnTransportEvent -= HandleNetworkEvent;
@@ -1092,8 +1525,8 @@ namespace Unity.Netcode
         internal int SendMessage<T>(ref T message, NetworkDelivery delivery, ulong clientId)
             where T : INetworkMessage
         {
-            // Prevent server sending to itself
-            if (LocalClient.IsServer && clientId == NetworkManager.ServerClientId)
+            // Prevent server sending to itself or if there is no MessageManager yet then exit early
+            if ((LocalClient.IsServer && clientId == NetworkManager.ServerClientId) || MessageManager == null)
             {
                 return 0;
             }

Runtime/Core/NetworkBehaviour.cs

@@ -6,6 +6,14 @@ using UnityEngine;
 
 namespace Unity.Netcode
 {
+    public class RpcException : Exception
+    {
+        public RpcException(string message) : base(message)
+        {
+
+        }
+    }
+
     /// <summary>
     /// The base class to override to write network code. Inherits MonoBehaviour
     /// </summary>
@@ -27,16 +35,22 @@ namespace Unity.Netcode
         // RuntimeAccessModifiersILPP will make this `protected`
         internal enum __RpcExecStage
         {
+            // Technically will overlap with None and Server
+            // but it doesn't matter since we don't use None and Server
+            Send = 0,
+            Execute = 1,
+
+            // Backward compatibility, not used...
             None = 0,
             Server = 1,
-            Client = 2
+            Client = 2,
         }
         // NetworkBehaviourILPP will override this in derived classes to return the name of the concrete type
         internal virtual string __getTypeName() => nameof(NetworkBehaviour);
 
         [NonSerialized]
         // RuntimeAccessModifiersILPP will make this `protected`
-        internal __RpcExecStage __rpc_exec_stage = __RpcExecStage.None;
+        internal __RpcExecStage __rpc_exec_stage = __RpcExecStage.Send;
 #pragma warning restore IDE1006 // restore naming rule violation check
 
         private const int k_RpcMessageDefaultSize = 1024; // 1k
@@ -55,6 +69,7 @@ namespace Unity.Netcode
         internal void __endSendServerRpc(ref FastBufferWriter bufferWriter, uint rpcMethodId, ServerRpcParams serverRpcParams, RpcDelivery rpcDelivery)
 #pragma warning restore IDE1006 // restore naming rule violation check
         {
+            var networkManager = NetworkManager;
             var serverRpcMessage = new ServerRpcMessage
             {
                 Metadata = new RpcMetadata
@@ -74,7 +89,7 @@ namespace Unity.Netcode
                     networkDelivery = NetworkDelivery.ReliableFragmentedSequenced;
                     break;
                 case RpcDelivery.Unreliable:
-                    if (bufferWriter.Length > NetworkManager.MessageManager.NonFragmentedMessageMaxSize)
+                    if (bufferWriter.Length > networkManager.MessageManager.NonFragmentedMessageMaxSize)
                     {
                         throw new OverflowException("RPC parameters are too large for unreliable delivery.");
                     }
@@ -83,16 +98,16 @@ namespace Unity.Netcode
             }
 
             var rpcWriteSize = 0;
-
-            // If we are a server/host then we just no op and send to ourself
-            if (IsHost || IsServer)
+            // Authority just no ops and sends to itself
+            // Client-Server: Only the server-host sends to self
+            if (IsServer)
             {
                 using var tempBuffer = new FastBufferReader(bufferWriter, Allocator.Temp);
                 var context = new NetworkContext
                 {
                     SenderId = NetworkManager.ServerClientId,
-                    Timestamp = NetworkManager.RealTimeProvider.RealTimeSinceStartup,
-                    SystemOwner = NetworkManager,
+                    Timestamp = networkManager.RealTimeProvider.RealTimeSinceStartup,
+                    SystemOwner = networkManager,
                     // header information isn't valid since it's not a real message.
                     // RpcMessage doesn't access this stuff so it's just left empty.
                     Header = new NetworkMessageHeader(),
@@ -135,6 +150,7 @@ namespace Unity.Netcode
         internal void __endSendClientRpc(ref FastBufferWriter bufferWriter, uint rpcMethodId, ClientRpcParams clientRpcParams, RpcDelivery rpcDelivery)
 #pragma warning restore IDE1006 // restore naming rule violation check
         {
+            var networkManager = NetworkManager;
             var clientRpcMessage = new ClientRpcMessage
             {
                 Metadata = new RpcMetadata
@@ -154,7 +170,7 @@ namespace Unity.Netcode
                     networkDelivery = NetworkDelivery.ReliableFragmentedSequenced;
                     break;
                 case RpcDelivery.Unreliable:
-                    if (bufferWriter.Length > NetworkManager.MessageManager.NonFragmentedMessageMaxSize)
+                    if (bufferWriter.Length > networkManager.MessageManager.NonFragmentedMessageMaxSize)
                     {
                         throw new OverflowException("RPC parameters are too large for unreliable delivery.");
                     }
@@ -166,24 +182,22 @@ namespace Unity.Netcode
 
             // We check to see if we need to shortcut for the case where we are the host/server and we can send a clientRPC
             // to ourself. Sadly we have to figure that out from the list of clientIds :(
-            bool shouldSendToHost = false;
+            bool shouldInvokeLocally = false;
             if (clientRpcParams.Send.TargetClientIds != null)
             {
                 foreach (var targetClientId in clientRpcParams.Send.TargetClientIds)
                 {
                     if (targetClientId == NetworkManager.ServerClientId)
                     {
-                        shouldSendToHost = true;
-                        break;
+                        shouldInvokeLocally = true;
+                        continue;
                     }
-
                     // Check to make sure we are sending to only observers, if not log an error.
-                    if (NetworkManager.LogLevel >= LogLevel.Error && !NetworkObject.Observers.Contains(targetClientId))
+                    if (networkManager.LogLevel >= LogLevel.Error && !NetworkObject.Observers.Contains(targetClientId))
                     {
                         NetworkLog.LogError(GenerateObserverErrorMessage(clientRpcParams, targetClientId));
                     }
                 }
-
                 rpcWriteSize = NetworkManager.ConnectionManager.SendMessage(ref clientRpcMessage, networkDelivery, in clientRpcParams.Send.TargetClientIds);
             }
             else if (clientRpcParams.Send.TargetClientIdsNativeArray != null)
@@ -192,17 +206,15 @@ namespace Unity.Netcode
                 {
                     if (targetClientId == NetworkManager.ServerClientId)
                     {
-                        shouldSendToHost = true;
-                        break;
+                        shouldInvokeLocally = true;
+                        continue;
                     }
-
                     // Check to make sure we are sending to only observers, if not log an error.
-                    if (NetworkManager.LogLevel >= LogLevel.Error && !NetworkObject.Observers.Contains(targetClientId))
+                    if (networkManager.LogLevel >= LogLevel.Error && !NetworkObject.Observers.Contains(targetClientId))
                     {
                         NetworkLog.LogError(GenerateObserverErrorMessage(clientRpcParams, targetClientId));
                     }
                 }
-
                 rpcWriteSize = NetworkManager.ConnectionManager.SendMessage(ref clientRpcMessage, networkDelivery, clientRpcParams.Send.TargetClientIdsNativeArray.Value);
             }
             else
@@ -213,7 +225,7 @@ namespace Unity.Netcode
                     // Skip over the host
                     if (IsHost && observerEnumerator.Current == NetworkManager.LocalClientId)
                     {
-                        shouldSendToHost = true;
+                        shouldInvokeLocally = true;
                         continue;
                     }
                     rpcWriteSize = NetworkManager.ConnectionManager.SendMessage(ref clientRpcMessage, networkDelivery, observerEnumerator.Current);
@@ -221,14 +233,14 @@ namespace Unity.Netcode
             }
 
             // If we are a server/host then we just no op and send to ourself
-            if (shouldSendToHost)
+            if (shouldInvokeLocally)
             {
                 using var tempBuffer = new FastBufferReader(bufferWriter, Allocator.Temp);
                 var context = new NetworkContext
                 {
                     SenderId = NetworkManager.ServerClientId,
-                    Timestamp = NetworkManager.RealTimeProvider.RealTimeSinceStartup,
-                    SystemOwner = NetworkManager,
+                    Timestamp = networkManager.RealTimeProvider.RealTimeSinceStartup,
+                    SystemOwner = networkManager,
                     // header information isn't valid since it's not a real message.
                     // RpcMessage doesn't access this stuff so it's just left empty.
                     Header = new NetworkMessageHeader(),
@@ -247,7 +259,7 @@ namespace Unity.Netcode
                 {
                     foreach (var targetClientId in clientRpcParams.Send.TargetClientIds)
                     {
-                        NetworkManager.NetworkMetrics.TrackRpcSent(
+                        networkManager.NetworkMetrics.TrackRpcSent(
                             targetClientId,
                             NetworkObject,
                             rpcMethodName,
@@ -259,7 +271,7 @@ namespace Unity.Netcode
                 {
                     foreach (var targetClientId in clientRpcParams.Send.TargetClientIdsNativeArray)
                     {
-                        NetworkManager.NetworkMetrics.TrackRpcSent(
+                        networkManager.NetworkMetrics.TrackRpcSent(
                             targetClientId,
                             NetworkObject,
                             rpcMethodName,
@@ -272,7 +284,7 @@ namespace Unity.Netcode
                     var observerEnumerator = NetworkObject.Observers.GetEnumerator();
                     while (observerEnumerator.MoveNext())
                     {
-                        NetworkManager.NetworkMetrics.TrackRpcSent(
+                        networkManager.NetworkMetrics.TrackRpcSent(
                             observerEnumerator.Current,
                             NetworkObject,
                             rpcMethodName,
@@ -284,6 +296,105 @@ namespace Unity.Netcode
 #endif
         }
 
+
+#pragma warning disable IDE1006 // disable naming rule violation check
+        // RuntimeAccessModifiersILPP will make this `protected`
+        internal FastBufferWriter __beginSendRpc(uint rpcMethodId, RpcParams rpcParams, RpcAttribute.RpcAttributeParams attributeParams, SendTo defaultTarget, RpcDelivery rpcDelivery)
+#pragma warning restore IDE1006 // restore naming rule violation check
+        {
+            if (attributeParams.RequireOwnership && !IsOwner)
+            {
+                throw new RpcException("This RPC can only be sent by its owner.");
+            }
+            return new FastBufferWriter(k_RpcMessageDefaultSize, Allocator.Temp, k_RpcMessageMaximumSize);
+        }
+
+#pragma warning disable IDE1006 // disable naming rule violation check
+        // RuntimeAccessModifiersILPP will make this `protected`
+        internal void __endSendRpc(ref FastBufferWriter bufferWriter, uint rpcMethodId, RpcParams rpcParams, RpcAttribute.RpcAttributeParams attributeParams, SendTo defaultTarget, RpcDelivery rpcDelivery)
+#pragma warning restore IDE1006 // restore naming rule violation check
+        {
+            var rpcMessage = new RpcMessage
+            {
+                Metadata = new RpcMetadata
+                {
+                    NetworkObjectId = NetworkObjectId,
+                    NetworkBehaviourId = NetworkBehaviourId,
+                    NetworkRpcMethodId = rpcMethodId,
+                },
+                SenderClientId = NetworkManager.LocalClientId,
+                WriteBuffer = bufferWriter
+            };
+
+            NetworkDelivery networkDelivery;
+            switch (rpcDelivery)
+            {
+                default:
+                case RpcDelivery.Reliable:
+                    networkDelivery = NetworkDelivery.ReliableFragmentedSequenced;
+                    break;
+                case RpcDelivery.Unreliable:
+                    if (bufferWriter.Length > NetworkManager.MessageManager.NonFragmentedMessageMaxSize)
+                    {
+                        throw new OverflowException("RPC parameters are too large for unreliable delivery.");
+                    }
+                    networkDelivery = NetworkDelivery.Unreliable;
+                    break;
+            }
+
+            if (rpcParams.Send.Target == null)
+            {
+                switch (defaultTarget)
+                {
+                    case SendTo.Everyone:
+                        rpcParams.Send.Target = RpcTarget.Everyone;
+                        break;
+                    case SendTo.Owner:
+                        rpcParams.Send.Target = RpcTarget.Owner;
+                        break;
+                    case SendTo.Server:
+                        rpcParams.Send.Target = RpcTarget.Server;
+                        break;
+                    case SendTo.NotServer:
+                        rpcParams.Send.Target = RpcTarget.NotServer;
+                        break;
+                    case SendTo.NotMe:
+                        rpcParams.Send.Target = RpcTarget.NotMe;
+                        break;
+                    case SendTo.NotOwner:
+                        rpcParams.Send.Target = RpcTarget.NotOwner;
+                        break;
+                    case SendTo.Me:
+                        rpcParams.Send.Target = RpcTarget.Me;
+                        break;
+                    case SendTo.ClientsAndHost:
+                        rpcParams.Send.Target = RpcTarget.ClientsAndHost;
+                        break;
+                    case SendTo.Authority:
+                        rpcParams.Send.Target = RpcTarget.Authority;
+                        break;
+                    case SendTo.NotAuthority:
+                        rpcParams.Send.Target = RpcTarget.NotAuthority;
+                        break;
+                    case SendTo.SpecifiedInParams:
+                        throw new RpcException("This method requires a runtime-specified send target.");
+                }
+            }
+            else if (defaultTarget != SendTo.SpecifiedInParams && !attributeParams.AllowTargetOverride)
+            {
+                throw new RpcException("Target override is not allowed for this method.");
+            }
+
+            if (rpcParams.Send.LocalDeferMode == LocalDeferMode.Default)
+            {
+                rpcParams.Send.LocalDeferMode = attributeParams.DeferLocal ? LocalDeferMode.Defer : LocalDeferMode.SendImmediate;
+            }
+
+            rpcParams.Send.Target.Send(this, ref rpcMessage, networkDelivery, rpcParams);
+
+            bufferWriter.Dispose();
+        }
+
 #pragma warning disable IDE1006 // disable naming rule violation check
         // RuntimeAccessModifiersILPP will make this `protected`
         internal static NativeList<T> __createNativeList<T>() where T : unmanaged
@@ -315,6 +426,24 @@ namespace Unity.Netcode
             }
         }
 
+        // This erroneously tries to simplify these method references but the docs do not pick it up correctly
+        // because they try to resolve it on the field rather than the class of the same name.
+#pragma warning disable IDE0001
+        /// <summary>
+        /// Provides access to the various <see cref="SendTo"/> targets at runtime, as well as
+        /// runtime-bound targets like <see cref="Unity.Netcode.RpcTarget.Single"/>,
+        /// <see cref="Unity.Netcode.RpcTarget.Group(NativeArray{ulong})"/>,
+        /// <see cref="Unity.Netcode.RpcTarget.Group(NativeList{ulong})"/>,
+        /// <see cref="Unity.Netcode.RpcTarget.Group(ulong[])"/>,
+        /// <see cref="Unity.Netcode.RpcTarget.Group{T}(T)"/>, <see cref="Unity.Netcode.RpcTarget.Not(ulong)"/>,
+        /// <see cref="Unity.Netcode.RpcTarget.Not(NativeArray{ulong})"/>,
+        /// <see cref="Unity.Netcode.RpcTarget.Not(NativeList{ulong})"/>,
+        /// <see cref="Unity.Netcode.RpcTarget.Not(ulong[])"/>, and
+        /// <see cref="Unity.Netcode.RpcTarget.Not{T}(T)"/>
+        /// </summary>
+#pragma warning restore IDE0001
+        public RpcTarget RpcTarget => NetworkManager.RpcTarget;
+
         /// <summary>
         /// If a NetworkObject is assigned, it will return whether or not this NetworkObject
         /// is the local player object.  If no NetworkObject is assigned it will always return false.
@@ -331,6 +460,36 @@ namespace Unity.Netcode
         /// </summary>
         public bool IsServer { get; private set; }
 
+        /// <summary>
+        /// Determines if the local client has authority over the associated NetworkObject
+        /// Client-Server: This will return true if IsServer or IsHost
+        /// Distributed Authority: This will return true if IsOwner
+        /// </summary>
+        public bool HasAuthority { get; internal set; }
+
+        internal NetworkClient LocalClient { get; private set; }
+
+        /// <summary>
+        /// Gets if the client is the distributed authority mode session owner
+        /// </summary>
+        public bool IsSessionOwner
+        {
+            get
+            {
+                if (LocalClient == null)
+                {
+                    return false;
+                }
+
+                return LocalClient.IsSessionOwner;
+            }
+        }
+
+        /// <summary>
+        /// Gets if the server (local or remote) is a host - i.e., also a client
+        /// </summary>
+        public bool ServerIsHost { get; private set; }
+
         /// <summary>
         /// Gets if we are executing as client
         /// </summary>
@@ -375,12 +534,14 @@ namespace Unity.Netcode
         {
             get
             {
+                if (m_NetworkObject != null)
+                {
+                    return m_NetworkObject;
+                }
+
                 try
                 {
-                    if (m_NetworkObject == null)
-                    {
-                        m_NetworkObject = GetComponentInParent<NetworkObject>();
-                    }
+                    m_NetworkObject = GetComponentInParent<NetworkObject>();
                 }
                 catch (Exception)
                 {
@@ -449,39 +610,56 @@ namespace Unity.Netcode
         /// </summary>
         internal void UpdateNetworkProperties()
         {
+            var networkObject = NetworkObject;
             // Set NetworkObject dependent properties
-            if (NetworkObject != null)
+            if (networkObject != null)
             {
+                var networkManager = NetworkManager;
                 // Set identification related properties
-                NetworkObjectId = NetworkObject.NetworkObjectId;
-                IsLocalPlayer = NetworkObject.IsLocalPlayer;
+                NetworkObjectId = networkObject.NetworkObjectId;
+                IsLocalPlayer = networkObject.IsLocalPlayer;
 
                 // This is "OK" because GetNetworkBehaviourOrderIndex uses the order of
                 // NetworkObject.ChildNetworkBehaviours which is set once when first
                 // accessed.
-                NetworkBehaviourId = NetworkObject.GetNetworkBehaviourOrderIndex(this);
+                NetworkBehaviourId = networkObject.GetNetworkBehaviourOrderIndex(this);
 
                 // Set ownership related properties
-                IsOwnedByServer = NetworkObject.IsOwnedByServer;
-                IsOwner = NetworkObject.IsOwner;
-                OwnerClientId = NetworkObject.OwnerClientId;
+                IsOwnedByServer = networkObject.IsOwnedByServer;
+                IsOwner = networkObject.IsOwner;
+                OwnerClientId = networkObject.OwnerClientId;
 
                 // Set NetworkManager dependent properties
-                if (NetworkManager != null)
+                if (networkManager != null)
                 {
-                    IsHost = NetworkManager.IsListening && NetworkManager.IsHost;
-                    IsClient = NetworkManager.IsListening && NetworkManager.IsClient;
-                    IsServer = NetworkManager.IsListening && NetworkManager.IsServer;
+                    IsHost = networkManager.IsListening && networkManager.IsHost;
+                    IsClient = networkManager.IsListening && networkManager.IsClient;
+                    IsServer = networkManager.IsListening && networkManager.IsServer;
+                    LocalClient = networkManager.LocalClient;
+                    HasAuthority = networkObject.HasAuthority;
+                    ServerIsHost = networkManager.IsListening && networkManager.ServerIsHost;
                 }
             }
             else // Shouldn't happen, but if so then set the properties to their default value;
             {
                 OwnerClientId = NetworkObjectId = default;
-                IsOwnedByServer = IsOwner = IsHost = IsClient = IsServer = default;
+                IsOwnedByServer = IsOwner = IsHost = IsClient = IsServer = ServerIsHost = default;
                 NetworkBehaviourId = default;
+                LocalClient = default;
+                HasAuthority = default;
             }
         }
 
+        /// <summary>
+        /// Distributed Authority Mode Only
+        /// Invoked only on the authority instance when a <see cref="NetworkObject"/> is deferring its despawn on non-authoritative instances.
+        /// </summary>
+        /// <remarks>
+        /// See also: <see cref="NetworkObject.DeferDespawn(int, bool)"/>
+        /// </remarks>
+        /// <param name="despawnTick">the future network tick that the <see cref="NetworkObject"/> will be despawned on non-authoritative instances</param>
+        public virtual void OnDeferringDespawn(int despawnTick) { }
+
         /// <summary>
         /// Gets called when the <see cref="NetworkObject"/> gets spawned, message handlers are ready to be registered and the network is setup.
         /// </summary>
@@ -511,7 +689,8 @@ namespace Unity.Netcode
             }
 
             InitializeVariables();
-            if (IsServer)
+
+            if (NetworkObject.HasAuthority)
             {
                 // Since we just spawned the object and since user code might have modified their NetworkVariable, esp.
                 // NetworkList, we need to mark the object as free of updates.
@@ -548,7 +727,7 @@ namespace Unity.Netcode
         /// <summary>
         /// Invoked on all clients, override this method to be notified of any
         /// ownership changes (even if the instance was niether the previous or
-        /// newly assigned current owner). 
+        /// newly assigned current owner).
         /// </summary>
         /// <param name="previous">the previous owner</param>
         /// <param name="current">the current owner</param>
@@ -707,65 +886,83 @@ namespace Unity.Netcode
             PreNetworkVariableWrite();
         }
 
-        internal void VariableUpdate(ulong targetClientId)
-        {
-            NetworkVariableUpdate(targetClientId, NetworkBehaviourId);
-        }
-
         internal readonly List<int> NetworkVariableIndexesToReset = new List<int>();
         internal readonly HashSet<int> NetworkVariableIndexesToResetSet = new HashSet<int>();
 
-        private void NetworkVariableUpdate(ulong targetClientId, int behaviourIndex)
+        internal void NetworkVariableUpdate(ulong targetClientId)
         {
             if (!CouldHaveDirtyNetworkVariables())
             {
                 return;
             }
 
+            // Getting these ahead of time actually improves performance
+            var networkManager = NetworkManager;
+            var networkObject = NetworkObject;
+            var behaviourIndex = networkObject.GetNetworkBehaviourOrderIndex(this);
+            var messageManager = networkManager.MessageManager;
+            var connectionManager = networkManager.ConnectionManager;
+
             for (int j = 0; j < m_DeliveryMappedNetworkVariableIndices.Count; j++)
             {
+                var networkVariable = (NetworkVariableBase)null;
                 var shouldSend = false;
                 for (int k = 0; k < NetworkVariableFields.Count; k++)
                 {
-                    var networkVariable = NetworkVariableFields[k];
+                    networkVariable = NetworkVariableFields[k];
                     if (networkVariable.IsDirty() && networkVariable.CanClientRead(targetClientId))
                     {
                         shouldSend = true;
                         break;
                     }
                 }
-
-                if (shouldSend)
+                // All of this is just to prevent the DA Host from re-sending a NetworkVariable update it received from the client owner
+                // If this NetworkManager is running as a DAHost:
+                // - Only when the write permissions is owner (to pass existing integration tests running as DAHost)
+                // - If the target client ID is the owner and the owner is not the local NetworkManager instance
+                // - **Special** As long as ownership did not just change and we are sending the new owner any dirty/updated NetworkVariables
+                // Under these conditions we should not send to the client
+                if (shouldSend && networkManager.DAHost && networkVariable.WritePerm == NetworkVariableWritePermission.Owner &&
+                    networkObject.OwnerClientId == targetClientId && networkObject.OwnerClientId != networkManager.LocalClientId &&
+                    networkObject.PreviousOwnerId == networkObject.OwnerClientId)
                 {
-                    var message = new NetworkVariableDeltaMessage
+                    shouldSend = false;
+                }
+
+                if (!shouldSend)
+                {
+                    continue;
+                }
+                var message = new NetworkVariableDeltaMessage
+                {
+                    NetworkObjectId = NetworkObjectId,
+                    NetworkBehaviourIndex = behaviourIndex,
+                    NetworkBehaviour = this,
+                    TargetClientId = targetClientId,
+                    DeliveryMappedNetworkVariableIndex = m_DeliveryMappedNetworkVariableIndices[j]
+                };
+                // TODO: Serialization is where the IsDirty flag gets changed.
+                // Messages don't get sent from the server to itself, so if we're host and sending to ourselves,
+                // we still have to actually serialize the message even though we're not sending it, otherwise
+                // the dirty flag doesn't change properly. These two pieces should be decoupled at some point
+                // so we don't have to do this serialization work if we're not going to use the result.
+                if (IsServer && targetClientId == NetworkManager.ServerClientId)
+                {
+                    var tmpWriter = new FastBufferWriter(messageManager.NonFragmentedMessageMaxSize, Allocator.Temp, messageManager.FragmentedMessageMaxSize);
+                    using (tmpWriter)
                     {
-                        NetworkObjectId = NetworkObjectId,
-                        NetworkBehaviourIndex = NetworkObject.GetNetworkBehaviourOrderIndex(this),
-                        NetworkBehaviour = this,
-                        TargetClientId = targetClientId,
-                        DeliveryMappedNetworkVariableIndex = m_DeliveryMappedNetworkVariableIndices[j]
-                    };
-                    // TODO: Serialization is where the IsDirty flag gets changed.
-                    // Messages don't get sent from the server to itself, so if we're host and sending to ourselves,
-                    // we still have to actually serialize the message even though we're not sending it, otherwise
-                    // the dirty flag doesn't change properly. These two pieces should be decoupled at some point
-                    // so we don't have to do this serialization work if we're not going to use the result.
-                    if (IsServer && targetClientId == NetworkManager.ServerClientId)
-                    {
-                        var tmpWriter = new FastBufferWriter(NetworkManager.MessageManager.NonFragmentedMessageMaxSize, Allocator.Temp, NetworkManager.MessageManager.FragmentedMessageMaxSize);
-                        using (tmpWriter)
-                        {
-                            message.Serialize(tmpWriter, message.Version);
-                        }
-                    }
-                    else
-                    {
-                        NetworkManager.ConnectionManager.SendMessage(ref message, m_DeliveryTypesForNetworkVariableGroups[j], targetClientId);
+                        message.Serialize(tmpWriter, message.Version);
                     }
                 }
+                else
+                {
+                    connectionManager.SendMessage(ref message, m_DeliveryTypesForNetworkVariableGroups[j], targetClientId);
+                }
             }
         }
 
+        internal static bool LogSentVariableUpdateMessage;
+
         private bool CouldHaveDirtyNetworkVariables()
         {
             // TODO: There should be a better way by reading one dirty variable vs. 'n'
@@ -798,17 +995,30 @@ namespace Unity.Netcode
         /// </remarks>
         internal void WriteNetworkVariableData(FastBufferWriter writer, ulong targetClientId)
         {
+            var networkManager = NetworkManager;
+            if (networkManager.DistributedAuthorityMode)
+            {
+                writer.WriteValueSafe((ushort)NetworkVariableFields.Count);
+            }
+
             if (NetworkVariableFields.Count == 0)
             {
                 return;
             }
 
+            // DANGO-TODO: Made some modifications here that overlap/won't play nice with EnsureNetworkVariableLenghtSafety.
+            // Worth either merging or more cleanly separating these codepaths.
             for (int j = 0; j < NetworkVariableFields.Count; j++)
             {
-
+                // Note: In distributed authority mode, all clients can read
                 if (NetworkVariableFields[j].CanClientRead(targetClientId))
                 {
-                    if (NetworkManager.NetworkConfig.EnsureNetworkVariableLengthSafety)
+                    if (networkManager.DistributedAuthorityMode)
+                    {
+                        writer.WriteValueSafe(NetworkVariableFields[j].Type);
+                    }
+
+                    if (networkManager.DistributedAuthorityMode || networkManager.NetworkConfig.EnsureNetworkVariableLengthSafety)
                     {
                         var writePos = writer.Position;
                         // Note: This value can't be packed because we don't know how large it will be in advance
@@ -829,10 +1039,13 @@ namespace Unity.Netcode
                         NetworkVariableFields[j].WriteField(writer);
                     }
                 }
-                else // Only if EnsureNetworkVariableLengthSafety, otherwise just skip
-                if (NetworkManager.NetworkConfig.EnsureNetworkVariableLengthSafety)
+                else
                 {
-                    writer.WriteValueSafe((ushort)0);
+                    // Only if EnsureNetworkVariableLengthSafety, otherwise just skip
+                    if (networkManager.DistributedAuthorityMode || networkManager.NetworkConfig.EnsureNetworkVariableLengthSafety)
+                    {
+                        writer.WriteValueSafe((ushort)0);
+                    }
                 }
             }
         }
@@ -847,16 +1060,29 @@ namespace Unity.Netcode
         /// </remarks>
         internal void SetNetworkVariableData(FastBufferReader reader, ulong clientId)
         {
+            var networkManager = NetworkManager;
+            if (networkManager.DistributedAuthorityMode)
+            {
+                reader.ReadValueSafe(out ushort variableCount);
+                if (variableCount != NetworkVariableFields.Count)
+                {
+                    Debug.LogError("NetworkVariable count mismatch.");
+                    return;
+                }
+            }
+
             if (NetworkVariableFields.Count == 0)
             {
                 return;
             }
 
+            // DANGO-TODO: Made some modifications here that overlap/won't play nice with EnsureNetworkVariableLenghtSafety.
+            // Worth either merging or more cleanly separating these codepaths.
             for (int j = 0; j < NetworkVariableFields.Count; j++)
             {
                 var varSize = (ushort)0;
                 var readStartPos = 0;
-                if (NetworkManager.NetworkConfig.EnsureNetworkVariableLengthSafety)
+                if (networkManager.NetworkConfig.EnsureNetworkVariableLengthSafety)
                 {
                     reader.ReadValueSafe(out varSize);
                     if (varSize == 0)
@@ -868,12 +1094,35 @@ namespace Unity.Netcode
                 else // If the client cannot read this field, then skip it
                 if (!NetworkVariableFields[j].CanClientRead(clientId))
                 {
+                    if (networkManager.DistributedAuthorityMode)
+                    {
+                        reader.ReadValueSafe(out ushort size);
+                        if (size != 0)
+                        {
+                            Debug.LogError("Expected zero size");
+                        }
+                    }
                     continue;
                 }
 
-                NetworkVariableFields[j].ReadField(reader);
+                if (networkManager.DistributedAuthorityMode)
+                {
+                    // Explicit setting of the NetworkVariableType is only needed for CMB Runtime
+                    reader.ReadValueSafe(out NetworkVariableType _);
+                    reader.ReadValueSafe(out ushort size);
+                    var start_marker = reader.Position;
+                    NetworkVariableFields[j].ReadField(reader);
+                    if (reader.Position - start_marker != size)
+                    {
+                        Debug.LogError("Mismatched network variable size");
+                    }
+                }
+                else
+                {
+                    NetworkVariableFields[j].ReadField(reader);
+                }
 
-                if (NetworkManager.NetworkConfig.EnsureNetworkVariableLengthSafety)
+                if (networkManager.NetworkConfig.EnsureNetworkVariableLengthSafety)
                 {
                     if (reader.Position > (readStartPos + varSize))
                     {
@@ -993,6 +1242,8 @@ namespace Unity.Netcode
                 if (finalPosition == positionBeforeSynchronize || threwException)
                 {
                     writer.Seek(positionBeforeWrite);
+                    // Truncate back to the size before
+                    writer.Truncate();
                     return false;
                 }
                 else
@@ -1037,7 +1288,7 @@ namespace Unity.Netcode
                 {
                     if (NetworkManager.LogLevel <= LogLevel.Normal)
                     {
-                        NetworkLog.LogWarning($"{name} read {totalBytesRead} bytes but was expected to read {expectedBytesToRead} bytes during synchronization deserialization! This {nameof(NetworkBehaviour)} is being skipped and will not be synchronized!");
+                        NetworkLog.LogWarning($"{name} read {totalBytesRead} bytes but was expected to read {expectedBytesToRead} bytes during synchronization deserialization! This {nameof(NetworkBehaviour)}({GetType().Name})is being skipped and will not be synchronized!");
                     }
                     synchronizationError = true;
                 }

Runtime/Core/NetworkBehaviourUpdater.cs

@@ -44,13 +44,12 @@ namespace Unity.Netcode
                         for (int i = 0; i < m_ConnectionManager.ConnectedClientsList.Count; i++)
                         {
                             var client = m_ConnectionManager.ConnectedClientsList[i];
-
-                            if (dirtyObj.IsNetworkVisibleTo(client.ClientId))
+                            if (m_NetworkManager.DistributedAuthorityMode || dirtyObj.IsNetworkVisibleTo(client.ClientId))
                             {
                                 // Sync just the variables for just the objects this client sees
                                 for (int k = 0; k < dirtyObj.ChildNetworkBehaviours.Count; k++)
                                 {
-                                    dirtyObj.ChildNetworkBehaviours[k].VariableUpdate(client.ClientId);
+                                    dirtyObj.ChildNetworkBehaviours[k].NetworkVariableUpdate(client.ClientId);
                                 }
                             }
                         }
@@ -69,7 +68,7 @@ namespace Unity.Netcode
                             }
                             for (int k = 0; k < sobj.ChildNetworkBehaviours.Count; k++)
                             {
-                                sobj.ChildNetworkBehaviours[k].VariableUpdate(NetworkManager.ServerClientId);
+                                sobj.ChildNetworkBehaviours[k].NetworkVariableUpdate(NetworkManager.ServerClientId);
                             }
                         }
                     }
@@ -95,6 +94,8 @@ namespace Unity.Netcode
                 foreach (var dirtyobj in m_DirtyNetworkObjects)
                 {
                     dirtyobj.PostNetworkVariableWrite();
+                    // Once done processing, we set the previous owner id to the current owner id
+                    dirtyobj.PreviousOwnerId = dirtyobj.OwnerClientId;
                 }
                 m_DirtyNetworkObjects.Clear();
             }

Runtime/Core/NetworkManager.cs

@@ -1,5 +1,7 @@
 using System;
 using System.Collections.Generic;
+using Unity.Collections;
+using System.Linq;
 using UnityEngine;
 #if UNITY_EDITOR
 using UnityEditor;
@@ -33,6 +35,148 @@ namespace Unity.Netcode
 
 #pragma warning restore IDE1006 // restore naming rule violation check
 
+        /// <summary>
+        /// Distributed Authority Mode
+        /// Returns true if the current session is running in distributed authority mode.
+        /// </summary>
+        public bool DistributedAuthorityMode
+        {
+            get
+            {
+                return NetworkConfig.SessionMode == SessionModeTypes.DistributedAuthority;
+            }
+        }
+
+        /// <summary>
+        /// Distributed Authority Mode
+        /// Gets whether the NetworkManager is connected to a distributed authority state service.
+        /// <see cref="NetworkClient.DAHost"/> to determine if the instance is mocking the state service.
+        /// </summary>
+        public bool CMBServiceConnection
+        {
+            get
+            {
+                return NetworkConfig.UseCMBService;
+            }
+        }
+
+        /// <summary>
+        /// Distributed Authority Mode
+        /// When enabled, the player prefab will be automatically spawned on the newly connected client-side.
+        /// </summary>
+        /// <remarks>
+        /// Refer to <see cref="NetworkConfig.AutoSpawnPlayerPrefabClientSide"/> to enable/disable automatic spawning of the player prefab.
+        /// Alternately, override the <see cref="FetchLocalPlayerPrefabToSpawn"/> to control what prefab the player should spawn.
+        /// </remarks>
+        public bool AutoSpawnPlayerPrefabClientSide
+        {
+            get
+            {
+                return NetworkConfig.AutoSpawnPlayerPrefabClientSide;
+            }
+        }
+
+        /// <summary>
+        /// Distributed Authority Mode
+        /// Delegate definition for <see cref="FetchLocalPlayerPrefabToSpawn"/>
+        /// </summary>
+        /// <returns>Player Prefab <see cref="GameObject"/></returns>
+        public delegate GameObject OnFetchLocalPlayerPrefabToSpawnDelegateHandler();
+
+        /// <summary>
+        /// Distributed Authority Mode
+        /// When a callback is assigned, this provides control over what player prefab a client will be using.
+        /// This is invoked only when <see cref="NetworkConfig.AutoSpawnPlayerPrefabClientSide"/> is enabled.
+        /// </summary>
+        public OnFetchLocalPlayerPrefabToSpawnDelegateHandler OnFetchLocalPlayerPrefabToSpawn;
+
+        internal GameObject FetchLocalPlayerPrefabToSpawn()
+        {
+            if (!AutoSpawnPlayerPrefabClientSide)
+            {
+                Debug.LogError($"[{nameof(FetchLocalPlayerPrefabToSpawn)}] Invoked when {nameof(NetworkConfig.AutoSpawnPlayerPrefabClientSide)} was not set! Check call paths!");
+                return null;
+            }
+            if (OnFetchLocalPlayerPrefabToSpawn == null && NetworkConfig.PlayerPrefab == null)
+            {
+                return null;
+            }
+
+            if (OnFetchLocalPlayerPrefabToSpawn != null)
+            {
+                return OnFetchLocalPlayerPrefabToSpawn();
+            }
+            return NetworkConfig.PlayerPrefab;
+        }
+
+        /// <summary>
+        /// Distributed Authority Mode
+        /// Gets whether the current NetworkManager is running as a mock distributed authority state service (DAHost)
+        /// </summary>
+        public bool DAHost
+        {
+            get
+            {
+                return LocalClient.DAHost;
+            }
+        }
+
+        // DANGO-TODO-MVP: Remove these properties once the service handles object distribution
+        internal ulong ClientToRedistribute;
+        internal bool RedistributeToClient;
+        internal int TickToRedistribute;
+
+        internal List<NetworkObject> DeferredDespawnObjects = new List<NetworkObject>();
+
+        public ulong CurrentSessionOwner { get; internal set; }
+
+        internal void SetSessionOwner(ulong sessionOwner)
+        {
+            var previousSessionOwner = CurrentSessionOwner;
+            CurrentSessionOwner = sessionOwner;
+            LocalClient.IsSessionOwner = LocalClientId == sessionOwner;
+            if (LocalClient.IsSessionOwner)
+            {
+                foreach (var networkObjectEntry in SpawnManager.SpawnedObjects)
+                {
+                    var networkObject = networkObjectEntry.Value;
+                    if (networkObject.IsSceneObject == null || !networkObject.IsSceneObject.Value)
+                    {
+                        continue;
+                    }
+                    if (networkObject.OwnerClientId != LocalClientId)
+                    {
+                        SpawnManager.ChangeOwnership(networkObject, LocalClientId, true);
+                    }
+                }
+            }
+        }
+
+        // TODO: Make this internal after testing
+        public void PromoteSessionOwner(ulong clientId)
+        {
+            if (!DistributedAuthorityMode)
+            {
+                NetworkLog.LogErrorServer($"[SceneManagement][NotDA] Invoking promote session owner while not in distributed authority mode!");
+                return;
+            }
+            if (!DAHost)
+            {
+                NetworkLog.LogErrorServer($"[SceneManagement][NotDAHost] Client is attempting to promote another client as the session owner!");
+                return;
+            }
+            SetSessionOwner(clientId);
+            var sessionOwnerMessage = new SessionOwnerMessage()
+            {
+                SessionOwner = clientId,
+            };
+            var clients = ConnectionManager.ConnectedClientIds.Where(c => c != LocalClientId).ToArray();
+            foreach (var targetClient in clients)
+            {
+                ConnectionManager.SendMessage(ref sessionOwnerMessage, NetworkDelivery.ReliableSequenced, targetClient);
+            }
+        }
+
         public void NetworkUpdate(NetworkUpdateStage updateStage)
         {
             switch (updateStage)
@@ -42,6 +186,8 @@ namespace Unity.Netcode
                         ConnectionManager.ProcessPendingApprovals();
                         ConnectionManager.PollAndHandleNetworkEvents();
 
+                        DeferredMessageManager.ProcessTriggers(IDeferredNetworkMessageManager.TriggerType.OnNextFrame, 0);
+
                         MessageManager.ProcessIncomingMessageQueue();
                         MessageManager.CleanupDisconnectedClients();
                     }
@@ -53,6 +199,15 @@ namespace Unity.Netcode
                     break;
                 case NetworkUpdateStage.PostLateUpdate:
                     {
+                        // Handle deferred despawning
+                        if (DistributedAuthorityMode)
+                        {
+                            SpawnManager.DeferredDespawnUpdate(ServerTime);
+                        }
+
+                        // Update any NetworkObject's registered to notify of scene migration changes.
+                        NetworkObject.UpdateNetworkObjectSceneChanges();
+
                         // This should be invoked just prior to the MessageManager processes its outbound queue.
                         SceneManager.CheckForAndSendNetworkObjectSceneChanged();
 
@@ -68,15 +223,101 @@ namespace Unity.Netcode
                         // This is "ok" to invoke when not processing messages since it is just cleaning up messages that never got handled within their timeout period.
                         DeferredMessageManager.CleanupStaleTriggers();
 
+                        // DANGO-TODO-MVP: Remove this once the service handles object distribution
+                        // NOTE: This needs to be the last thing done and should happen exactly at this point
+                        // in the update
+                        if (RedistributeToClient && ServerTime.Tick <= TickToRedistribute)
+                        {
+                            RedistributeToClient = false;
+                            SpawnManager.DistributeNetworkObjects(ClientToRedistribute);
+                            ClientToRedistribute = 0;
+                        }
+
                         if (m_ShuttingDown)
                         {
-                            ShutdownInternal();
+                            // Host-server will disconnect any connected clients prior to finalizing its shutdown
+                            if (IsServer)
+                            {
+                                ProcessServerShutdown();
+                            }
+                            else
+                            {
+                                // Clients just disconnect immediately
+                                ShutdownInternal();
+                            }
                         }
                     }
                     break;
             }
         }
 
+        /// <summary>
+        /// Used to provide a graceful shutdown sequence
+        /// </summary>
+        internal enum ServerShutdownStates
+        {
+            None,
+            WaitForClientDisconnects,
+            InternalShutdown,
+            ShuttingDown,
+        };
+
+        internal ServerShutdownStates ServerShutdownState;
+        private float m_ShutdownTimeout;
+
+        /// <summary>
+        /// This is a "soft shutdown" where the host or server will disconnect
+        /// all clients, with a provided reasons, prior to invoking its final
+        /// internal shutdown.
+        /// </summary>
+        internal void ProcessServerShutdown()
+        {
+            var minClientCount = IsHost ? 2 : 1;
+            switch (ServerShutdownState)
+            {
+                case ServerShutdownStates.None:
+                    {
+                        if (ConnectedClients.Count >= minClientCount)
+                        {
+                            var hostServer = IsHost ? "host" : "server";
+                            var disconnectReason = $"Disconnected due to {hostServer} shutting down.";
+                            for (int i = ConnectedClientsIds.Count - 1; i >= 0; i--)
+                            {
+                                var clientId = ConnectedClientsIds[i];
+                                if (clientId == ServerClientId)
+                                {
+                                    continue;
+                                }
+                                ConnectionManager.DisconnectClient(clientId, disconnectReason);
+                            }
+                            ServerShutdownState = ServerShutdownStates.WaitForClientDisconnects;
+                            m_ShutdownTimeout = Time.realtimeSinceStartup + 5.0f;
+                        }
+                        else
+                        {
+                            ServerShutdownState = ServerShutdownStates.InternalShutdown;
+                            ProcessServerShutdown();
+                        }
+                        break;
+                    }
+                case ServerShutdownStates.WaitForClientDisconnects:
+                    {
+                        if (ConnectedClients.Count < minClientCount || m_ShutdownTimeout < Time.realtimeSinceStartup)
+                        {
+                            ServerShutdownState = ServerShutdownStates.InternalShutdown;
+                            ProcessServerShutdown();
+                        }
+                        break;
+                    }
+                case ServerShutdownStates.InternalShutdown:
+                    {
+                        ServerShutdownState = ServerShutdownStates.ShuttingDown;
+                        ShutdownInternal();
+                        break;
+                    }
+            }
+        }
+
         /// <summary>
         /// The client id used to represent the server
         /// </summary>
@@ -92,19 +333,19 @@ namespace Unity.Netcode
         }
 
         /// <summary>
-        /// Gets a dictionary of connected clients and their clientId keys. This is only accessible on the server.
+        /// Gets a dictionary of connected clients and their clientId keys.
         /// </summary>
-        public IReadOnlyDictionary<ulong, NetworkClient> ConnectedClients => IsServer ? ConnectionManager.ConnectedClients : throw new NotServerException($"{nameof(ConnectionManager.ConnectedClients)} should only be accessed on server.");
+        public IReadOnlyDictionary<ulong, NetworkClient> ConnectedClients => ConnectionManager.ConnectedClients;
 
         /// <summary>
-        /// Gets a list of connected clients. This is only accessible on the server.
+        /// Gets a list of connected clients.
         /// </summary>
-        public IReadOnlyList<NetworkClient> ConnectedClientsList => IsServer ? ConnectionManager.ConnectedClientsList : throw new NotServerException($"{nameof(ConnectionManager.ConnectedClientsList)} should only be accessed on server.");
+        public IReadOnlyList<NetworkClient> ConnectedClientsList => ConnectionManager.ConnectedClientsList;
 
         /// <summary>
-        /// Gets a list of just the IDs of all connected clients. This is only accessible on the server.
+        /// Gets a list of just the IDs of all connected clients.
         /// </summary>
-        public IReadOnlyList<ulong> ConnectedClientsIds => IsServer ? ConnectionManager.ConnectedClientIds : throw new NotServerException($"{nameof(ConnectionManager.ConnectedClientIds)} should only be accessed on server.");
+        public IReadOnlyList<ulong> ConnectedClientsIds => ConnectionManager.ConnectedClientIds;
 
         /// <summary>
         /// Gets the local <see cref="NetworkClient"/> for this client.
@@ -122,6 +363,11 @@ namespace Unity.Netcode
         /// </summary>
         public bool IsServer => ConnectionManager.LocalClient.IsServer;
 
+        /// <summary>
+        /// Gets whether or not the current server (local or remote) is a host - i.e., also a client
+        /// </summary>
+        public bool ServerIsHost => ConnectionManager.ConnectedClientIds.Contains(ServerClientId);
+
         /// <summary>
         /// Gets Whether or not a client is running
         /// </summary>
@@ -209,6 +455,8 @@ namespace Unity.Netcode
 
         /// <summary>
         /// The callback to invoke once a client connects. This callback is only ran on the server and on the local client that connects.
+        ///
+        /// It is recommended to use OnConnectionEvent instead, as this will eventually be deprecated
         /// </summary>
         public event Action<ulong> OnClientConnectedCallback
         {
@@ -218,6 +466,8 @@ namespace Unity.Netcode
 
         /// <summary>
         /// The callback to invoke when a client disconnects. This callback is only ran on the server and on the local client that disconnects.
+        ///
+        /// It is recommended to use OnConnectionEvent instead, as this will eventually be deprecated
         /// </summary>
         public event Action<ulong> OnClientDisconnectCallback
         {
@@ -225,6 +475,16 @@ namespace Unity.Netcode
             remove => ConnectionManager.OnClientDisconnectCallback -= value;
         }
 
+        /// <summary>
+        /// The callback to invoke on any connection event. See <see cref="ConnectionEvent"/> and <see cref="ConnectionEventData"/>
+        /// for more info.
+        /// </summary>
+        public event Action<NetworkManager, ConnectionEventData> OnConnectionEvent
+        {
+            add => ConnectionManager.OnConnectionEvent += value;
+            remove => ConnectionManager.OnConnectionEvent -= value;
+        }
+
         /// <summary>
         /// The current host name we are connected to, used to validate certificate
         /// </summary>
@@ -379,6 +639,24 @@ namespace Unity.Netcode
 
         internal IDeferredNetworkMessageManager DeferredMessageManager { get; private set; }
 
+        // This erroneously tries to simplify these method references but the docs do not pick it up correctly
+        // because they try to resolve it on the field rather than the class of the same name.
+#pragma warning disable IDE0001
+        /// <summary>
+        /// Provides access to the various <see cref="SendTo"/> targets at runtime, as well as
+        /// runtime-bound targets like <see cref="Unity.Netcode.RpcTarget.Single"/>,
+        /// <see cref="Unity.Netcode.RpcTarget.Group(NativeArray{ulong})"/>,
+        /// <see cref="Unity.Netcode.RpcTarget.Group(NativeList{ulong})"/>,
+        /// <see cref="Unity.Netcode.RpcTarget.Group(ulong[])"/>,
+        /// <see cref="Unity.Netcode.RpcTarget.Group{T}(T)"/>, <see cref="Unity.Netcode.RpcTarget.Not(ulong)"/>,
+        /// <see cref="Unity.Netcode.RpcTarget.Not(NativeArray{ulong})"/>,
+        /// <see cref="Unity.Netcode.RpcTarget.Not(NativeList{ulong})"/>,
+        /// <see cref="Unity.Netcode.RpcTarget.Not(ulong[])"/>, and
+        /// <see cref="Unity.Netcode.RpcTarget.Not{T}(T)"/>
+        /// </summary>
+#pragma warning restore IDE0001
+        public RpcTarget RpcTarget;
+
         /// <summary>
         /// Gets the CustomMessagingManager for this NetworkManager
         /// </summary>
@@ -412,6 +690,19 @@ namespace Unity.Netcode
         internal NetworkConnectionManager ConnectionManager = new NetworkConnectionManager();
         internal NetworkMessageManager MessageManager = null;
 
+        internal struct Override<T>
+        {
+            private T m_Value;
+            public bool Overidden { get; private set; }
+            internal T Value
+            {
+                get { return Overidden ? m_Value : default(T); }
+                set { Overidden = true; m_Value = value; }
+            }
+        };
+
+        internal Override<ushort> PortOverride;
+
 #if UNITY_EDITOR
         internal static INetworkManagerHelper NetworkManagerHelper;
 
@@ -651,6 +942,16 @@ namespace Unity.Netcode
 
         internal void Initialize(bool server)
         {
+
+            //DANGOEXP TODO: Remove this before finalizing the experimental release
+            NetworkConfig.AutoSpawnPlayerPrefabClientSide = DistributedAuthorityMode;
+
+            // Make sure the ServerShutdownState is reset when initializing
+            if (server)
+            {
+                ServerShutdownState = ServerShutdownStates.None;
+            }
+
             // Don't allow the user to start a network session if the NetworkManager is
             // still parented under another GameObject
             if (NetworkManagerCheckForParent(true))
@@ -658,6 +959,8 @@ namespace Unity.Netcode
                 return;
             }
 
+            ParseCommandLineOptions();
+
             if (NetworkConfig.NetworkTransport == null)
             {
                 if (NetworkLog.CurrentLogLevel <= LogLevel.Error)
@@ -714,6 +1017,8 @@ namespace Unity.Netcode
 
             DeferredMessageManager = ComponentFactory.Create<IDeferredNetworkMessageManager>(this);
 
+            RpcTarget = new RpcTarget(this);
+
             CustomMessagingManager = new CustomMessagingManager(this);
 
             SceneManager = new NetworkSceneManager(this);
@@ -791,7 +1096,10 @@ namespace Unity.Netcode
                 return false;
             }
 
-            ConnectionManager.LocalClient.SetRole(true, false, this);
+            if (!ConnectionManager.LocalClient.SetRole(true, false, this))
+            {
+                return false;
+            }
             ConnectionManager.LocalClient.ClientId = ServerClientId;
 
             Initialize(true);
@@ -837,7 +1145,10 @@ namespace Unity.Netcode
                 return false;
             }
 
-            ConnectionManager.LocalClient.SetRole(false, true, this);
+            if (!ConnectionManager.LocalClient.SetRole(false, true, this))
+            {
+                return false;
+            }
 
             Initialize(false);
 
@@ -880,7 +1191,11 @@ namespace Unity.Netcode
                 return false;
             }
 
-            ConnectionManager.LocalClient.SetRole(true, true, this);
+            if (!ConnectionManager.LocalClient.SetRole(true, true, this))
+            {
+                return false;
+            }
+
             Initialize(true);
             try
             {
@@ -914,6 +1229,7 @@ namespace Unity.Netcode
         {
             LocalClientId = ServerClientId;
             NetworkMetrics.SetConnectionId(LocalClientId);
+            MessageManager.SetLocalClientId(LocalClientId);
 
             if (NetworkConfig.ConnectionApproval && ConnectionApprovalCallback != null)
             {
@@ -935,7 +1251,8 @@ namespace Unity.Netcode
                 var response = new ConnectionApprovalResponse
                 {
                     Approved = true,
-                    CreatePlayerObject = NetworkConfig.PlayerPrefab != null
+                    // Distributed authority always returns true since the client side handles spawning (whether automatically or manually)
+                    CreatePlayerObject = DistributedAuthorityMode || NetworkConfig.PlayerPrefab != null,
                 };
                 ConnectionManager.HandleConnectionApproval(ServerClientId, response);
             }
@@ -992,11 +1309,6 @@ namespace Unity.Netcode
                     MessageManager.StopProcessing = discardMessageQueue;
                 }
             }
-
-            if (NetworkConfig != null && NetworkConfig.NetworkTransport != null)
-            {
-                NetworkConfig.NetworkTransport.OnTransportEvent -= ConnectionManager.HandleNetworkEvent;
-            }
         }
 
         // Ensures that the NetworkManager is cleaned up before OnDestroy is run on NetworkObjects and NetworkBehaviours when unloading a scene with a NetworkManager
@@ -1021,6 +1333,9 @@ namespace Unity.Netcode
             DeferredMessageManager?.CleanupAllTriggers();
             CustomMessagingManager = null;
 
+            RpcTarget?.Dispose();
+            RpcTarget = null;
+
             BehaviourUpdater?.Shutdown();
             BehaviourUpdater = null;
 
@@ -1047,6 +1362,12 @@ namespace Unity.Netcode
             IsListening = false;
             m_ShuttingDown = false;
 
+            // Generate a local notification that the host client is disconnected
+            if (IsHost)
+            {
+                ConnectionManager.InvokeOnClientDisconnectCallback(LocalClientId);
+            }
+
             if (ConnectionManager.LocalClient.IsClient)
             {
                 // If we were a client, we want to know if we were a host
@@ -1080,6 +1401,7 @@ namespace Unity.Netcode
             NetworkTickSystem = null;
         }
 
+
         // Ensures that the NetworkManager is cleaned up before OnDestroy is run on NetworkObjects and NetworkBehaviours when quitting the application.
         private void OnApplicationQuit()
         {
@@ -1100,5 +1422,39 @@ namespace Unity.Netcode
                 Singleton = null;
             }
         }
+
+        // Command line options
+        private const string k_OverridePortArg = "-port";
+
+        private string GetArg(string[] commandLineArgs, string arg)
+        {
+            var argIndex = Array.IndexOf(commandLineArgs, arg);
+            if (argIndex >= 0 && argIndex < commandLineArgs.Length - 1)
+            {
+                return commandLineArgs[argIndex + 1];
+            }
+
+            return null;
+        }
+
+        private void ParseArg<T>(string arg, ref Override<T> value)
+        {
+            if (GetArg(Environment.GetCommandLineArgs(), arg) is string argValue)
+            {
+                value.Value = (T)Convert.ChangeType(argValue, typeof(T));
+            }
+        }
+
+        private void ParseCommandLineOptions()
+        {
+#if UNITY_SERVER && UNITY_DEDICATED_SERVER_ARGUMENTS_PRESENT
+            if ( UnityEngine.DedicatedServer.Arguments.Port != null)
+            {
+                PortOverride.Value = (ushort)UnityEngine.DedicatedServer.Arguments.Port;
+            }
+#else
+            ParseArg(k_OverridePortArg, ref PortOverride);
+#endif
+        }
     }
 }

Runtime/Logging/NetworkLog.cs

@@ -39,6 +39,12 @@ namespace Unity.Netcode
         /// <param name="message">The message to log</param>
         public static void LogInfoServer(string message) => LogServer(message, LogType.Info);
 
+        /// <summary>
+        /// Logs an info log locally and on the session owner if possible.
+        /// </summary>
+        /// <param name="message">The message to log</param>
+        public static void LogInfoSessionOwner(string message) => LogServer(message, LogType.Info);
+
         /// <summary>
         /// Logs a warning log locally and on the server if possible.
         /// </summary>
@@ -58,7 +64,8 @@ namespace Unity.Netcode
             var networkManager = NetworkManagerOverride ??= NetworkManager.Singleton;
             // Get the sender of the local log
             ulong localId = networkManager?.LocalClientId ?? 0;
-            bool isServer = networkManager?.IsServer ?? true;
+            bool isServer = networkManager && networkManager.DistributedAuthorityMode ? networkManager.LocalClient.IsSessionOwner :
+                networkManager && !networkManager.DistributedAuthorityMode ? networkManager.IsServer : true;
             switch (logType)
             {
                 case LogType.Info:
@@ -98,7 +105,8 @@ namespace Unity.Netcode
                 var networkMessage = new ServerLogMessage
                 {
                     LogType = logType,
-                    Message = message
+                    Message = message,
+                    SenderId = localId
                 };
                 var size = networkManager.ConnectionManager.SendMessage(ref networkMessage, NetworkDelivery.ReliableFragmentedSequenced, NetworkManager.ServerClientId);
 
@@ -106,9 +114,19 @@ namespace Unity.Netcode
             }
         }
 
-        internal static void LogInfoServerLocal(string message, ulong sender) => Debug.Log($"[Netcode-Server Sender={sender}] {message}");
-        internal static void LogWarningServerLocal(string message, ulong sender) => Debug.LogWarning($"[Netcode-Server Sender={sender}] {message}");
-        internal static void LogErrorServerLocal(string message, ulong sender) => Debug.LogError($"[Netcode-Server Sender={sender}] {message}");
+        private static string Header()
+        {
+            var networkManager = NetworkManagerOverride ??= NetworkManager.Singleton;
+            if (networkManager.DistributedAuthorityMode)
+            {
+                return "Session-Owner";
+            }
+            return "Netcode-Server";
+        }
+
+        internal static void LogInfoServerLocal(string message, ulong sender) => Debug.Log($"[{Header()} Sender={sender}] {message}");
+        internal static void LogWarningServerLocal(string message, ulong sender) => Debug.LogWarning($"[{Header()} Sender={sender}] {message}");
+        internal static void LogErrorServerLocal(string message, ulong sender) => Debug.LogError($"[{Header()} Sender={sender}] {message}");
 
         internal enum LogType : byte
         {

Runtime/Messaging/CustomMessageManager.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using Unity.Collections;
+using UnityEngine;
 
 namespace Unity.Netcode
 {
@@ -151,18 +152,14 @@ namespace Unity.Netcode
                 // We dont know what size to use. Try every (more collision prone)
                 if (m_NamedMessageHandlers32.TryGetValue(hash, out HandleNamedMessageDelegate messageHandler32))
                 {
-                    // handler can remove itself, cache the name for metrics
-                    string messageName = m_MessageHandlerNameLookup32[hash];
                     messageHandler32(sender, reader);
-                    m_NetworkManager.NetworkMetrics.TrackNamedMessageReceived(sender, messageName, bytesCount);
+                    m_NetworkManager.NetworkMetrics.TrackNamedMessageReceived(sender, m_MessageHandlerNameLookup32[hash], bytesCount);
                 }
 
                 if (m_NamedMessageHandlers64.TryGetValue(hash, out HandleNamedMessageDelegate messageHandler64))
                 {
-                    // handler can remove itself, cache the name for metrics
-                    string messageName = m_MessageHandlerNameLookup64[hash];
                     messageHandler64(sender, reader);
-                    m_NetworkManager.NetworkMetrics.TrackNamedMessageReceived(sender, messageName, bytesCount);
+                    m_NetworkManager.NetworkMetrics.TrackNamedMessageReceived(sender, m_MessageHandlerNameLookup64[hash], bytesCount);
                 }
             }
             else
@@ -173,19 +170,15 @@ namespace Unity.Netcode
                     case HashSize.VarIntFourBytes:
                         if (m_NamedMessageHandlers32.TryGetValue(hash, out HandleNamedMessageDelegate messageHandler32))
                         {
-                            // handler can remove itself, cache the name for metrics
-                            string messageName = m_MessageHandlerNameLookup32[hash];
                             messageHandler32(sender, reader);
-                            m_NetworkManager.NetworkMetrics.TrackNamedMessageReceived(sender, messageName, bytesCount);
+                            m_NetworkManager.NetworkMetrics.TrackNamedMessageReceived(sender, m_MessageHandlerNameLookup32[hash], bytesCount);
                         }
                         break;
                     case HashSize.VarIntEightBytes:
                         if (m_NamedMessageHandlers64.TryGetValue(hash, out HandleNamedMessageDelegate messageHandler64))
                         {
-                            // handler can remove itself, cache the name for metrics
-                            string messageName = m_MessageHandlerNameLookup64[hash];
                             messageHandler64(sender, reader);
-                            m_NetworkManager.NetworkMetrics.TrackNamedMessageReceived(sender, messageName, bytesCount);
+                            m_NetworkManager.NetworkMetrics.TrackNamedMessageReceived(sender, m_MessageHandlerNameLookup64[hash], bytesCount);
                         }
                         break;
                 }
@@ -199,6 +192,14 @@ namespace Unity.Netcode
         /// <param name="callback">The callback to run when a named message is received.</param>
         public void RegisterNamedMessageHandler(string name, HandleNamedMessageDelegate callback)
         {
+            if (string.IsNullOrEmpty(name))
+            {
+                if (m_NetworkManager.LogLevel <= LogLevel.Error)
+                {
+                    Debug.LogError($"[{nameof(RegisterNamedMessageHandler)}] Cannot register a named message of type null or empty!");
+                }
+                return;
+            }
             var hash32 = XXHash.Hash32(name);
             var hash64 = XXHash.Hash64(name);
 
@@ -215,6 +216,15 @@ namespace Unity.Netcode
         /// <param name="name">The name of the message.</param>
         public void UnregisterNamedMessageHandler(string name)
         {
+            if (string.IsNullOrEmpty(name))
+            {
+                if (m_NetworkManager.LogLevel <= LogLevel.Error)
+                {
+                    Debug.LogError($"[{nameof(UnregisterNamedMessageHandler)}] Cannot unregister a named message of type null or empty!");
+                }
+                return;
+            }
+
             var hash32 = XXHash.Hash32(name);
             var hash64 = XXHash.Hash64(name);
 

Runtime/Messaging/DeferredMessageManager.cs

@@ -15,6 +15,7 @@ namespace Unity.Netcode
         }
         protected struct TriggerInfo
         {
+            public string MessageType;
             public float Expiry;
             public NativeList<TriggerData> TriggerData;
         }
@@ -36,7 +37,7 @@ namespace Unity.Netcode
         /// There is a one second maximum lifetime of triggers to avoid memory leaks. After one second has passed
         /// without the requested object ID being spawned, the triggers for it are automatically deleted.
         /// </summary>
-        public virtual unsafe void DeferMessage(IDeferredNetworkMessageManager.TriggerType trigger, ulong key, FastBufferReader reader, ref NetworkContext context)
+        public virtual unsafe void DeferMessage(IDeferredNetworkMessageManager.TriggerType trigger, ulong key, FastBufferReader reader, ref NetworkContext context, string messageType)
         {
             if (!m_Triggers.TryGetValue(trigger, out var triggers))
             {
@@ -48,6 +49,7 @@ namespace Unity.Netcode
             {
                 triggerInfo = new TriggerInfo
                 {
+                    MessageType = messageType,
                     Expiry = m_NetworkManager.RealTimeProvider.RealTimeSinceStartup + m_NetworkManager.NetworkConfig.SpawnTimeout,
                     TriggerData = new NativeList<TriggerData>(Allocator.Persistent)
                 };
@@ -90,11 +92,29 @@ namespace Unity.Netcode
             }
         }
 
+        /// <summary>
+        /// Used for testing purposes
+        /// </summary>
+        internal static bool IncludeMessageType = true;
+
+        private string GetWarningMessage(IDeferredNetworkMessageManager.TriggerType triggerType, ulong key, TriggerInfo triggerInfo, float spawnTimeout)
+        {
+            if (IncludeMessageType)
+            {
+                return $"[Deferred {triggerType}] Messages were received for a trigger of type {triggerInfo.MessageType} associated with id ({key}), but the {nameof(NetworkObject)} was not received within the timeout period {spawnTimeout} second(s).";
+            }
+            else
+            {
+                return $"Deferred messages were received for a trigger of type {triggerType} associated with id ({key}), but the {nameof(NetworkObject)} was not received within the timeout period {spawnTimeout} second(s).";
+            }
+        }
+
         protected virtual void PurgeTrigger(IDeferredNetworkMessageManager.TriggerType triggerType, ulong key, TriggerInfo triggerInfo)
         {
-            if (NetworkLog.CurrentLogLevel <= LogLevel.Normal)
+            var logLevel = m_NetworkManager.DistributedAuthorityMode ? LogLevel.Developer : LogLevel.Normal;
+            if (NetworkLog.CurrentLogLevel <= logLevel)
             {
-                NetworkLog.LogWarning($"Deferred messages were received for a trigger of type {triggerType} with key {key}, but that trigger was not received within within {m_NetworkManager.NetworkConfig.SpawnTimeout} second(s).");
+                NetworkLog.LogWarning(GetWarningMessage(triggerType, key, triggerInfo, m_NetworkManager.NetworkConfig.SpawnTimeout));
             }
 
             foreach (var data in triggerInfo.TriggerData)
@@ -113,6 +133,7 @@ namespace Unity.Netcode
                 // processed before the object is fully spawned. This must be the last thing done in the spawn process.
                 if (triggers.TryGetValue(key, out var triggerInfo))
                 {
+                    triggers.Remove(key);
                     foreach (var deferredMessage in triggerInfo.TriggerData)
                     {
                         // Reader will be disposed within HandleMessage
@@ -120,7 +141,6 @@ namespace Unity.Netcode
                     }
 
                     triggerInfo.TriggerData.Dispose();
-                    triggers.Remove(key);
                 }
             }
         }

Runtime/Messaging/IDeferredNetworkMessageManager.cs

@@ -1,3 +1,4 @@
+
 namespace Unity.Netcode
 {
     internal interface IDeferredNetworkMessageManager
@@ -6,6 +7,7 @@ namespace Unity.Netcode
         {
             OnSpawn,
             OnAddPrefab,
+            OnNextFrame,
         }
 
         /// <summary>
@@ -16,7 +18,7 @@ namespace Unity.Netcode
         /// There is a one second maximum lifetime of triggers to avoid memory leaks. After one second has passed
         /// without the requested object ID being spawned, the triggers for it are automatically deleted.
         /// </summary>
-        void DeferMessage(TriggerType trigger, ulong key, FastBufferReader reader, ref NetworkContext context);
+        void DeferMessage(TriggerType trigger, ulong key, FastBufferReader reader, ref NetworkContext context, string messageType = null);
 
         /// <summary>
         /// Cleans up any trigger that's existed for more than a second.

Runtime/Messaging/Messages/ChangeOwnershipMessage.cs

@@ -1,3 +1,4 @@
+
 namespace Unity.Netcode
 {
     internal struct ChangeOwnershipMessage : INetworkMessage, INetworkSerializeByMemcpy
@@ -6,11 +7,146 @@ namespace Unity.Netcode
 
         public ulong NetworkObjectId;
         public ulong OwnerClientId;
+        // DANGOEXP TODO: Remove these notes or change their format
+        // SERVICE NOTES:
+        // When forwarding the message to clients on the CMB Service side,
+        // you can set the ClientIdCount to 0 and skip writing the ClientIds.
+        // See the NetworkObjet.OwnershipRequest for more potential service side additions
+
+        /// <summary>
+        /// When requesting, RequestClientId is the requestor.
+        /// When approving, RequestClientId is the owner that approved.
+        /// When responding (only for denied), RequestClientId is the requestor 
+        /// </summary>
+        internal ulong RequestClientId;
+        internal int ClientIdCount;
+        internal ulong[] ClientIds;
+        internal bool DistributedAuthorityMode;
+        internal ushort OwnershipFlags;
+        internal byte OwnershipRequestResponseStatus;
+        private byte m_OwnershipMessageTypeFlags;
+
+        private const byte k_OwnershipChanging = 0x01;
+        private const byte k_OwnershipFlagsUpdate = 0x02;
+        private const byte k_RequestOwnership = 0x04;
+        private const byte k_RequestApproved = 0x08;
+        private const byte k_RequestDenied = 0x10;
+
+        // If no flags are set, then ownership is changing
+        internal bool OwnershipIsChanging
+        {
+            get
+            {
+                return GetFlag(k_OwnershipChanging);
+            }
+
+            set
+            {
+                SetFlag(value, k_OwnershipChanging);
+            }
+        }
+
+        internal bool OwnershipFlagsUpdate
+        {
+            get
+            {
+                return GetFlag(k_OwnershipFlagsUpdate);
+            }
+
+            set
+            {
+                SetFlag(value, k_OwnershipFlagsUpdate);
+            }
+        }
+
+        internal bool RequestOwnership
+        {
+            get
+            {
+                return GetFlag(k_RequestOwnership);
+            }
+
+            set
+            {
+                SetFlag(value, k_RequestOwnership);
+            }
+        }
+
+        internal bool RequestApproved
+        {
+            get
+            {
+                return GetFlag(k_RequestApproved);
+            }
+
+            set
+            {
+                SetFlag(value, k_RequestApproved);
+            }
+        }
+
+        internal bool RequestDenied
+        {
+            get
+            {
+                return GetFlag(k_RequestDenied);
+            }
+
+            set
+            {
+                SetFlag(value, k_RequestDenied);
+            }
+        }
+
+        private bool GetFlag(int flag)
+        {
+            return (m_OwnershipMessageTypeFlags & flag) != 0;
+        }
+
+        private void SetFlag(bool set, byte flag)
+        {
+            if (set) { m_OwnershipMessageTypeFlags = (byte)(m_OwnershipMessageTypeFlags | flag); }
+            else { m_OwnershipMessageTypeFlags = (byte)(m_OwnershipMessageTypeFlags & ~flag); }
+        }
 
         public void Serialize(FastBufferWriter writer, int targetVersion)
         {
             BytePacker.WriteValueBitPacked(writer, NetworkObjectId);
             BytePacker.WriteValueBitPacked(writer, OwnerClientId);
+            if (DistributedAuthorityMode)
+            {
+                BytePacker.WriteValueBitPacked(writer, ClientIdCount);
+                if (ClientIdCount > 0)
+                {
+                    if (ClientIdCount != ClientIds.Length)
+                    {
+                        throw new System.Exception($"[{nameof(ChangeOwnershipMessage)}] ClientIdCount is {ClientIdCount} but the ClientIds length is {ClientIds.Length}!");
+                    }
+                    foreach (var clientId in ClientIds)
+                    {
+                        BytePacker.WriteValueBitPacked(writer, clientId);
+                    }
+                }
+
+                writer.WriteValueSafe(m_OwnershipMessageTypeFlags);
+                if (OwnershipFlagsUpdate || OwnershipIsChanging)
+                {
+                    writer.WriteValueSafe(OwnershipFlags);
+                }
+
+                // When requesting, it is the requestor
+                // When approving, it is the owner that approved
+                // When denied, it is the requestor
+                if (RequestOwnership || RequestApproved || RequestDenied)
+                {
+                    writer.WriteValueSafe(RequestClientId);
+
+                    if (RequestDenied)
+                    {
+                        writer.WriteValueSafe(OwnershipRequestResponseStatus);
+                    }
+                }
+            }
         }
 
         public bool Deserialize(FastBufferReader reader, ref NetworkContext context, int receivedMessageVersion)
@@ -22,46 +158,241 @@ namespace Unity.Netcode
             }
             ByteUnpacker.ReadValueBitPacked(reader, out NetworkObjectId);
             ByteUnpacker.ReadValueBitPacked(reader, out OwnerClientId);
-            if (!networkManager.SpawnManager.SpawnedObjects.ContainsKey(NetworkObjectId))
+
+            if (networkManager.DistributedAuthorityMode)
             {
-                networkManager.DeferredMessageManager.DeferMessage(IDeferredNetworkMessageManager.TriggerType.OnSpawn, NetworkObjectId, reader, ref context);
-                return false;
+                ByteUnpacker.ReadValueBitPacked(reader, out ClientIdCount);
+                if (ClientIdCount > 0)
+                {
+                    ClientIds = new ulong[ClientIdCount];
+                    var clientId = (ulong)0;
+                    for (int i = 0; i < ClientIdCount; i++)
+                    {
+                        ByteUnpacker.ReadValueBitPacked(reader, out clientId);
+                        ClientIds[i] = clientId;
+                    }
+                }
+
+                reader.ReadValueSafe(out m_OwnershipMessageTypeFlags);
+                if (OwnershipFlagsUpdate || OwnershipIsChanging)
+                {
+                    reader.ReadValueSafe(out OwnershipFlags);
+                }
+
+                // When requesting, it is the requestor
+                // When approving, it is the owner that approved
+                // When denied, it is the requestor
+                if (RequestOwnership || RequestApproved || RequestDenied)
+                {
+                    reader.ReadValueSafe(out RequestClientId);
+
+                    if (RequestDenied)
+                    {
+                        reader.ReadValueSafe(out OwnershipRequestResponseStatus);
+                    }
+                }
             }
 
+            // If we are not a DAHost instance and the NetworkObject does not exist then defer it as it very likely is not spawned yet.
+            // Otherwise if we are the DAHost and it does not exist then we want to forward this message because when the NetworkObject
+            // is made visible again, the ownership flags and owner information will be synchronized with the DAHost by the current
+            // authority of the NetworkObject in question.
+            if (!networkManager.DAHost && !networkManager.SpawnManager.SpawnedObjects.ContainsKey(NetworkObjectId))
+            {
+                networkManager.DeferredMessageManager.DeferMessage(IDeferredNetworkMessageManager.TriggerType.OnSpawn, NetworkObjectId, reader, ref context, GetType().Name);
+                return false;
+            }
             return true;
         }
 
         public void Handle(ref NetworkContext context)
         {
             var networkManager = (NetworkManager)context.SystemOwner;
-            var networkObject = networkManager.SpawnManager.SpawnedObjects[NetworkObjectId];
-            var originalOwner = networkObject.OwnerClientId;
 
+            // If we are the DAHost then forward this message
+            if (networkManager.DAHost)
+            {
+                var clientList = ClientIdCount > 0 ? ClientIds : networkManager.ConnectedClientsIds;
+
+                var message = new ChangeOwnershipMessage()
+                {
+                    NetworkObjectId = NetworkObjectId,
+                    OwnerClientId = OwnerClientId,
+                    DistributedAuthorityMode = true,
+                    OwnershipFlags = OwnershipFlags,
+                    RequestClientId = RequestClientId,
+                    ClientIdCount = 0,
+                    m_OwnershipMessageTypeFlags = m_OwnershipMessageTypeFlags,
+                };
+
+                if (RequestDenied)
+                {
+                    // If the local DAHost's client is not the target, then forward to the target
+                    if (RequestClientId != networkManager.LocalClientId)
+                    {
+                        message.OwnershipRequestResponseStatus = OwnershipRequestResponseStatus;
+                        networkManager.ConnectionManager.SendMessage(ref message, NetworkDelivery.Reliable, RequestClientId);
+                        // We don't want the local DAHost's client to process this message, so exit early
+                        return;
+                    }
+                }
+                else if (RequestOwnership)
+                {
+                    // If the DAHost client is not authority, just forward the message to the authority
+                    if (OwnerClientId != networkManager.LocalClientId)
+                    {
+                        networkManager.ConnectionManager.SendMessage(ref message, NetworkDelivery.Reliable, OwnerClientId);
+                        // We don't want the local DAHost's client to process this message, so exit early
+                        return;
+                    }
+                    // Otherwise, fall through and process the request.
+                }
+                else
+                {
+                    foreach (var clientId in clientList)
+                    {
+                        if (clientId == networkManager.LocalClientId)
+                        {
+                            continue;
+                        }
+
+                        // If ownership is changing and this is not an ownership request approval then ignore the OnwerClientId
+                        // If it is just updating flags then ignore sending to the owner
+                        // If it is a request or approving request, then ignore the RequestClientId
+                        if ((OwnershipIsChanging && !RequestApproved && OwnerClientId == clientId) || (OwnershipFlagsUpdate && clientId == OwnerClientId)
+                            || ((RequestOwnership || RequestApproved) && clientId == RequestClientId))
+                        {
+                            continue;
+                        }
+
+                        networkManager.ConnectionManager.SendMessage(ref message, NetworkDelivery.Reliable, clientId);
+                    }
+                }
+                // If the NetworkObject is not visible to the DAHost client, then exit early 
+                if (!networkManager.SpawnManager.SpawnedObjects.ContainsKey(NetworkObjectId))
+                {
+                    return;
+                }
+            }
+
+            // If ownership is changing, then run through the ownershipd changed sequence
+            // Note: There is some extended ownership script at the bottom of HandleOwnershipChange
+            // If not in distributed authority mode, then always go straight to HandleOwnershipChange
+            if (OwnershipIsChanging || !networkManager.DistributedAuthorityMode)
+            {
+                HandleOwnershipChange(ref context);
+            }
+            else if (networkManager.DistributedAuthorityMode)
+            {
+                // Otherwise, we handle and extended ownership update
+                HandleExtendedOwnershipUpdate(ref context);
+            }
+        }
+
+        /// <summary>
+        /// Handle the 
+        /// </summary>
+        /// <param name="context"></param>
+        private void HandleExtendedOwnershipUpdate(ref NetworkContext context)
+        {
+            var networkManager = (NetworkManager)context.SystemOwner;
+
+            // Handle the extended ownership message types
+            var networkObject = networkManager.SpawnManager.SpawnedObjects[NetworkObjectId];
+
+            if (OwnershipFlagsUpdate)
+            {
+                // Just update the ownership flags
+                networkObject.Ownership = (NetworkObject.OwnershipStatus)OwnershipFlags;
+            }
+            else if (RequestOwnership)
+            {
+                // Requesting ownership, if allowed it will automatically send the ownership change message
+                networkObject.OwnershipRequest(RequestClientId);
+            }
+            else if (RequestDenied)
+            {
+                networkObject.OwnershipRequestResponse((NetworkObject.OwnershipRequestResponseStatus)OwnershipRequestResponseStatus);
+            }
+        }
+
+        /// <summary>
+        /// Handle the traditional change in ownership message type logic
+        /// </summary>
+        /// <param name="context"></param>
+        private void HandleOwnershipChange(ref NetworkContext context)
+        {
+            var networkManager = (NetworkManager)context.SystemOwner;
+            var networkObject = networkManager.SpawnManager.SpawnedObjects[NetworkObjectId];
+
+            // DANGO-TODO: This probably shouldn't be allowed to happen.
+            if (networkObject.OwnerClientId == OwnerClientId)
+            {
+                UnityEngine.Debug.LogWarning($"Unnecessary ownership changed message for {NetworkObjectId}");
+            }
+
+            var originalOwner = networkObject.OwnerClientId;
             networkObject.OwnerClientId = OwnerClientId;
 
-            // We are current owner.
-            if (originalOwner == networkManager.LocalClientId)
+            if (networkManager.DistributedAuthorityMode)
+            {
+                networkObject.Ownership = (NetworkObject.OwnershipStatus)OwnershipFlags;
+            }
+
+            // We are current owner (client-server) or running in distributed authority mode
+            if (originalOwner == networkManager.LocalClientId || networkManager.DistributedAuthorityMode)
             {
                 networkObject.InvokeBehaviourOnLostOwnership();
             }
 
-            // We are new owner.
-            if (OwnerClientId == networkManager.LocalClientId)
+            // We are new owner or (client-server) or running in distributed authority mode
+            if (OwnerClientId == networkManager.LocalClientId || networkManager.DistributedAuthorityMode)
             {
                 networkObject.InvokeBehaviourOnGainedOwnership();
             }
 
-            // For all other clients that are neither the former or current owner, update the behaviours' properties
-            if (OwnerClientId != networkManager.LocalClientId && originalOwner != networkManager.LocalClientId)
+            // If in distributed authority mode 
+            if (networkManager.DistributedAuthorityMode)
             {
+                // Always update the network properties in distributed authority mode 
                 for (int i = 0; i < networkObject.ChildNetworkBehaviours.Count; i++)
                 {
                     networkObject.ChildNetworkBehaviours[i].UpdateNetworkProperties();
                 }
             }
+            else // Otherwise update properties like we would in client-server
+            {
+                // For all other clients that are neither the former or current owner, update the behaviours' properties
+                if (OwnerClientId != networkManager.LocalClientId && originalOwner != networkManager.LocalClientId)
+                {
+                    for (int i = 0; i < networkObject.ChildNetworkBehaviours.Count; i++)
+                    {
+                        networkObject.ChildNetworkBehaviours[i].UpdateNetworkProperties();
+                    }
+                }
+            }
 
+            // Always invoke ownership change notifications
             networkObject.InvokeOwnershipChanged(originalOwner, OwnerClientId);
 
+            // If this change was requested, then notify that the request was approved (doing this last so all ownership
+            // changes have already been applied if the callback is invoked)
+            if (networkManager.DistributedAuthorityMode && networkManager.LocalClientId == OwnerClientId)
+            {
+                if (RequestApproved)
+                {
+                    networkObject.OwnershipRequestResponse(NetworkObject.OwnershipRequestResponseStatus.Approved);
+                }
+
+                // If the NetworkObject changed ownership and the Requested flag was set (i.e. it was an ownership request),
+                // then the new owner granted ownership removes the Requested flag and sends out an ownership status update.
+                if (networkObject.HasExtendedOwnershipStatus(NetworkObject.OwnershipStatusExtended.Requested))
+                {
+                    networkObject.RemoveOwnershipExtended(NetworkObject.OwnershipStatusExtended.Requested);
+                    networkObject.SendOwnershipStatusUpdate();
+                }
+            }
+
             networkManager.NetworkMetrics.TrackOwnershipChangeReceived(context.SenderId, networkObject, context.MessageSize);
         }
     }

Runtime/Messaging/Messages/ClientConnectedMessage.cs

@@ -0,0 +1,66 @@
+namespace Unity.Netcode
+{
+    internal struct ClientConnectedMessage : INetworkMessage, INetworkSerializeByMemcpy
+    {
+        public int Version => 0;
+
+        public ulong ClientId;
+
+        public bool ShouldSynchronize;
+
+
+        public void Serialize(FastBufferWriter writer, int targetVersion)
+        {
+            BytePacker.WriteValueBitPacked(writer, ClientId);
+            writer.WriteValueSafe(ShouldSynchronize);
+        }
+
+        public bool Deserialize(FastBufferReader reader, ref NetworkContext context, int receivedMessageVersion)
+        {
+            var networkManager = (NetworkManager)context.SystemOwner;
+            if (!networkManager.IsClient)
+            {
+                return false;
+            }
+            ByteUnpacker.ReadValueBitPacked(reader, out ClientId);
+            reader.ReadValueSafe(out ShouldSynchronize);
+
+            return true;
+        }
+
+        public void Handle(ref NetworkContext context)
+        {
+            var networkManager = (NetworkManager)context.SystemOwner;
+            if ((ShouldSynchronize || networkManager.CMBServiceConnection) && networkManager.DistributedAuthorityMode && networkManager.LocalClient.IsSessionOwner)
+            {
+                networkManager.SceneManager.SynchronizeNetworkObjects(ClientId);
+            }
+            else
+            {
+                // All modes support adding NetworkClients
+                networkManager.ConnectionManager.AddClient(ClientId);
+            }
+            if (!networkManager.ConnectionManager.ConnectedClientIds.Contains(ClientId))
+            {
+                networkManager.ConnectionManager.ConnectedClientIds.Add(ClientId);
+            }
+            if (networkManager.IsConnectedClient)
+            {
+                networkManager.ConnectionManager.InvokeOnPeerConnectedCallback(ClientId);
+            }
+
+            // DANGO-TODO: Remove the session owner object distribution check once the service handles object distribution
+            if (networkManager.DistributedAuthorityMode && networkManager.CMBServiceConnection && !networkManager.NetworkConfig.EnableSceneManagement)
+            {
+                // Don't redistribute for the local instance
+                if (ClientId != networkManager.LocalClientId)
+                {
+                    // We defer redistribution to the end of the NetworkUpdateStage.PostLateUpdate
+                    networkManager.RedistributeToClient = true;
+                    networkManager.ClientToRedistribute = ClientId;
+                    networkManager.TickToRedistribute = networkManager.ServerTime.Tick + 20;
+                }
+            }
+        }
+    }
+}

Runtime/Messaging/Messages/ClientConnectedMessage.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: 158454105806474cba54a4ea5a0bfb12
+timeCreated: 1697836112

Runtime/Messaging/Messages/ClientDisconnectedMessage.cs

@@ -0,0 +1,37 @@
+namespace Unity.Netcode
+{
+    internal struct ClientDisconnectedMessage : INetworkMessage, INetworkSerializeByMemcpy
+    {
+        public int Version => 0;
+
+        public ulong ClientId;
+
+        public void Serialize(FastBufferWriter writer, int targetVersion)
+        {
+            BytePacker.WriteValueBitPacked(writer, ClientId);
+        }
+
+        public bool Deserialize(FastBufferReader reader, ref NetworkContext context, int receivedMessageVersion)
+        {
+            var networkManager = (NetworkManager)context.SystemOwner;
+            if (!networkManager.IsClient)
+            {
+                return false;
+            }
+            ByteUnpacker.ReadValueBitPacked(reader, out ClientId);
+            return true;
+        }
+
+        public void Handle(ref NetworkContext context)
+        {
+            var networkManager = (NetworkManager)context.SystemOwner;
+            // All modes support removing NetworkClients
+            networkManager.ConnectionManager.RemoveClient(ClientId);
+            networkManager.ConnectionManager.ConnectedClientIds.Remove(ClientId);
+            if (networkManager.IsConnectedClient)
+            {
+                networkManager.ConnectionManager.InvokeOnPeerDisconnectedCallback(ClientId);
+            }
+        }
+    }
+}

Runtime/Messaging/Messages/ClientDisconnectedMessage.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: 8f91296c8e5f40b1a2a03d74a31526b6
+timeCreated: 1697836161

Runtime/Messaging/Messages/ConnectionApprovedMessage.cs

@@ -5,10 +5,16 @@ namespace Unity.Netcode
 {
     internal struct ConnectionApprovedMessage : INetworkMessage
     {
-        public int Version => 0;
+        private const int k_VersionAddClientIds = 1;
+        public int Version => k_VersionAddClientIds;
 
         public ulong OwnerClientId;
         public int NetworkTick;
+        // The cloud state service should set this if we are restoring a session
+        public bool IsRestoredSession;
+        public ulong CurrentSessionOwner;
+        // Not serialized
+        public bool IsDistributedAuthority;
 
         // Not serialized, held as references to serialize NetworkVariable data
         public HashSet<NetworkObject> SpawnedObjectsList;
@@ -17,6 +23,8 @@ namespace Unity.Netcode
 
         public NativeArray<MessageVersionData> MessageVersions;
 
+        public NativeArray<ulong> ConnectedClientIds;
+
         public void Serialize(FastBufferWriter writer, int targetVersion)
         {
             // ============================================================
@@ -35,6 +43,16 @@ namespace Unity.Netcode
 
             BytePacker.WriteValueBitPacked(writer, OwnerClientId);
             BytePacker.WriteValueBitPacked(writer, NetworkTick);
+            if (IsDistributedAuthority)
+            {
+                writer.WriteValueSafe(IsRestoredSession);
+                BytePacker.WriteValueBitPacked(writer, CurrentSessionOwner);
+            }
+
+            if (targetVersion >= k_VersionAddClientIds)
+            {
+                writer.WriteValueSafe(ConnectedClientIds);
+            }
 
             uint sceneObjectCount = 0;
 
@@ -51,7 +69,8 @@ namespace Unity.Netcode
                     if (sobj.SpawnWithObservers && (sobj.CheckObjectVisibility == null || sobj.CheckObjectVisibility(OwnerClientId)))
                     {
                         sobj.Observers.Add(OwnerClientId);
-                        var sceneObject = sobj.GetMessageSceneObject(OwnerClientId);
+                        // In distributed authority mode, we send the currently known observers of each NetworkObject to the client being synchronized.
+                        var sceneObject = sobj.GetMessageSceneObject(OwnerClientId, IsDistributedAuthority);
                         sceneObject.Serialize(writer);
                         ++sceneObjectCount;
                     }
@@ -106,6 +125,21 @@ namespace Unity.Netcode
 
             ByteUnpacker.ReadValueBitPacked(reader, out OwnerClientId);
             ByteUnpacker.ReadValueBitPacked(reader, out NetworkTick);
+            if (networkManager.DistributedAuthorityMode)
+            {
+                reader.ReadValueSafe(out IsRestoredSession);
+                ByteUnpacker.ReadValueBitPacked(reader, out CurrentSessionOwner);
+            }
+
+            if (receivedMessageVersion >= k_VersionAddClientIds)
+            {
+                reader.ReadValueSafe(out ConnectedClientIds, Allocator.TempJob);
+            }
+            else
+            {
+                ConnectedClientIds = new NativeArray<ulong>(0, Allocator.TempJob);
+            }
+
             m_ReceivedSceneObjectData = reader;
             return true;
         }
@@ -113,9 +147,23 @@ namespace Unity.Netcode
         public void Handle(ref NetworkContext context)
         {
             var networkManager = (NetworkManager)context.SystemOwner;
+            if (NetworkLog.CurrentLogLevel <= LogLevel.Developer)
+            {
+                NetworkLog.LogInfo($"[Client-{OwnerClientId}] Connection approved! Synchronizing...");
+            }
             networkManager.LocalClientId = OwnerClientId;
+            networkManager.MessageManager.SetLocalClientId(networkManager.LocalClientId);
             networkManager.NetworkMetrics.SetConnectionId(networkManager.LocalClientId);
 
+            if (networkManager.DistributedAuthorityMode)
+            {
+                networkManager.SetSessionOwner(CurrentSessionOwner);
+                if (networkManager.LocalClient.IsSessionOwner && networkManager.NetworkConfig.EnableSceneManagement)
+                {
+                    networkManager.SceneManager.InitializeScenesLoaded();
+                }
+            }
+
             var time = new NetworkTime(networkManager.NetworkTickSystem.TickRate, NetworkTick);
             networkManager.NetworkTimeSystem.Reset(time.Time, 0.15f); // Start with a constant RTT of 150 until we receive values from the transport.
             networkManager.NetworkTickSystem.Reset(networkManager.NetworkTimeSystem.LocalTime, networkManager.NetworkTimeSystem.ServerTime);
@@ -126,10 +174,29 @@ namespace Unity.Netcode
             // Stop the client-side approval timeout coroutine since we are approved.
             networkManager.ConnectionManager.StopClientApprovalCoroutine();
 
+            networkManager.ConnectionManager.ConnectedClientIds.Clear();
+            foreach (var clientId in ConnectedClientIds)
+            {
+                if (!networkManager.ConnectionManager.ConnectedClientIds.Contains(clientId))
+                {
+                    networkManager.ConnectionManager.AddClient(clientId);
+                }
+            }
+
             // Only if scene management is disabled do we handle NetworkObject synchronization at this point
             if (!networkManager.NetworkConfig.EnableSceneManagement)
             {
-                networkManager.SpawnManager.DestroySceneObjects();
+                // DANGO-TODO: This is a temporary fix for no DA CMB scene event handling.
+                // We will either use this same concept or provide some way for the CMB state plugin to handle it.
+                if (networkManager.DistributedAuthorityMode && networkManager.LocalClient.IsSessionOwner)
+                {
+                    networkManager.SpawnManager.ServerSpawnSceneObjectsOnStartSweep();
+                }
+                else
+                {
+                    networkManager.SpawnManager.DestroySceneObjects();
+                }
+
                 m_ReceivedSceneObjectData.ReadValueSafe(out uint sceneObjectCount);
 
                 // Deserializing NetworkVariable data is deferred from Receive() to Handle to avoid needing
@@ -143,9 +210,39 @@ namespace Unity.Netcode
 
                 // Mark the client being connected
                 networkManager.IsConnectedClient = true;
+
+                if (networkManager.AutoSpawnPlayerPrefabClientSide)
+                {
+                    networkManager.ConnectionManager.CreateAndSpawnPlayer(OwnerClientId);
+                }
+
+                if (NetworkLog.CurrentLogLevel <= LogLevel.Developer)
+                {
+                    NetworkLog.LogInfo($"[Client-{OwnerClientId}][Scene Management Disabled] Synchronization complete!");
+                }
                 // When scene management is disabled we notify after everything is synchronized
                 networkManager.ConnectionManager.InvokeOnClientConnectedCallback(context.SenderId);
             }
+            else
+            {
+                if (networkManager.DistributedAuthorityMode && networkManager.CMBServiceConnection && networkManager.LocalClient.IsSessionOwner && networkManager.NetworkConfig.EnableSceneManagement)
+                {
+                    // Mark the client being connected
+                    networkManager.IsConnectedClient = true;
+
+                    // Spawn any in-scene placed NetworkObjects
+                    networkManager.SpawnManager.ServerSpawnSceneObjectsOnStartSweep();
+
+                    // Spawn the local player of the session owner
+                    if (networkManager.AutoSpawnPlayerPrefabClientSide)
+                    {
+                        networkManager.ConnectionManager.CreateAndSpawnPlayer(OwnerClientId);
+                    }
+                    // Synchronize the service with the initial session owner's loaded scenes and spawned objects
+                    networkManager.SceneManager.SynchronizeNetworkObjects(NetworkManager.ServerClientId);
+                }
+            }
+            ConnectedClientIds.Dispose();
         }
     }
 }

Runtime/Messaging/Messages/ConnectionRequestMessage.cs

@@ -8,6 +8,10 @@ namespace Unity.Netcode
 
         public ulong ConfigHash;
 
+        public bool CMBServiceConnection;
+        public uint TickRate;
+        public bool EnableSceneManagement;
+
         public byte[] ConnectionData;
 
         public bool ShouldSendConnectionData;
@@ -30,6 +34,12 @@ namespace Unity.Netcode
             // END FORBIDDEN SEGMENT
             // ============================================================
 
+            if (CMBServiceConnection)
+            {
+                writer.WriteValueSafe(TickRate);
+                writer.WriteValueSafe(EnableSceneManagement);
+            }
+
             if (ShouldSendConnectionData)
             {
                 writer.WriteValueSafe(ConfigHash);
@@ -151,7 +161,7 @@ namespace Unity.Netcode
                 var response = new NetworkManager.ConnectionApprovalResponse
                 {
                     Approved = true,
-                    CreatePlayerObject = networkManager.NetworkConfig.PlayerPrefab != null
+                    CreatePlayerObject = networkManager.DistributedAuthorityMode && networkManager.AutoSpawnPlayerPrefabClientSide ? false : networkManager.NetworkConfig.PlayerPrefab != null
                 };
                 networkManager.ConnectionManager.HandleConnectionApproval(senderId, response);
             }

Runtime/Messaging/Messages/CreateObjectMessage.cs

@@ -1,3 +1,6 @@
+using System.Linq;
+using System.Runtime.CompilerServices;
+
 namespace Unity.Netcode
 {
     internal struct CreateObjectMessage : INetworkMessage
@@ -7,9 +10,109 @@ namespace Unity.Netcode
         public NetworkObject.SceneObject ObjectInfo;
         private FastBufferReader m_ReceivedNetworkVariableData;
 
+        // DA - NGO CMB SERVICE NOTES:
+        // The ObserverIds and ExistingObserverIds will only be populated if k_UpdateObservers is set
+        // ObserverIds is the full list of observers (see below)
+        internal ulong[] ObserverIds;
+
+        // While this does consume a bit more bandwidth, this is only sent by the authority/owner
+        // and can be used to determine which clients should receive the ObjectInfo serialized data.
+        // All other already existing observers just need to receive the NewObserverIds and the
+        // NetworkObjectId
+        internal ulong[] NewObserverIds;
+
+        // If !IncludesSerializedObject then the NetworkObjectId will be serialized.
+        // This happens when we are just sending an update to the observers list
+        // to clients that already have the NetworkObject spawned
+        internal ulong NetworkObjectId;
+
+        private const byte k_IncludesSerializedObject = 0x01;
+        private const byte k_UpdateObservers = 0x02;
+        private const byte k_UpdateNewObservers = 0x04;
+
+
+        private byte m_CreateObjectMessageTypeFlags;
+
+        internal bool IncludesSerializedObject
+        {
+            get
+            {
+                return GetFlag(k_IncludesSerializedObject);
+            }
+
+            set
+            {
+                SetFlag(value, k_IncludesSerializedObject);
+            }
+        }
+
+        internal bool UpdateObservers
+        {
+            get
+            {
+                return GetFlag(k_UpdateObservers);
+            }
+
+            set
+            {
+                SetFlag(value, k_UpdateObservers);
+            }
+        }
+
+        internal bool UpdateNewObservers
+        {
+            get
+            {
+                return GetFlag(k_UpdateNewObservers);
+            }
+
+            set
+            {
+                SetFlag(value, k_UpdateNewObservers);
+            }
+        }
+
+        private bool GetFlag(int flag)
+        {
+            return (m_CreateObjectMessageTypeFlags & flag) != 0;
+        }
+
+        private void SetFlag(bool set, byte flag)
+        {
+            if (set) { m_CreateObjectMessageTypeFlags = (byte)(m_CreateObjectMessageTypeFlags | flag); }
+            else { m_CreateObjectMessageTypeFlags = (byte)(m_CreateObjectMessageTypeFlags & ~flag); }
+        }
+
         public void Serialize(FastBufferWriter writer, int targetVersion)
         {
-            ObjectInfo.Serialize(writer);
+            writer.WriteValueSafe(m_CreateObjectMessageTypeFlags);
+
+            if (UpdateObservers)
+            {
+                BytePacker.WriteValuePacked(writer, ObserverIds.Length);
+                foreach (var clientId in ObserverIds)
+                {
+                    BytePacker.WriteValuePacked(writer, clientId);
+                }
+            }
+
+            if (UpdateNewObservers)
+            {
+                BytePacker.WriteValuePacked(writer, NewObserverIds.Length);
+                foreach (var clientId in NewObserverIds)
+                {
+                    BytePacker.WriteValuePacked(writer, clientId);
+                }
+            }
+
+            if (IncludesSerializedObject)
+            {
+                ObjectInfo.Serialize(writer);
+            }
+            else
+            {
+                BytePacker.WriteValuePacked(writer, NetworkObjectId);
+            }
         }
 
         public bool Deserialize(FastBufferReader reader, ref NetworkContext context, int receivedMessageVersion)
@@ -20,10 +123,45 @@ namespace Unity.Netcode
                 return false;
             }
 
-            ObjectInfo.Deserialize(reader);
+            reader.ReadValueSafe(out m_CreateObjectMessageTypeFlags);
+            if (UpdateObservers)
+            {
+                var length = 0;
+                ByteUnpacker.ReadValuePacked(reader, out length);
+                ObserverIds = new ulong[length];
+                var clientId = (ulong)0;
+                for (int i = 0; i < length; i++)
+                {
+                    ByteUnpacker.ReadValuePacked(reader, out clientId);
+                    ObserverIds[i] = clientId;
+                }
+            }
+
+            if (UpdateNewObservers)
+            {
+                var length = 0;
+                ByteUnpacker.ReadValuePacked(reader, out length);
+                NewObserverIds = new ulong[length];
+                var clientId = (ulong)0;
+                for (int i = 0; i < length; i++)
+                {
+                    ByteUnpacker.ReadValuePacked(reader, out clientId);
+                    NewObserverIds[i] = clientId;
+                }
+            }
+
+            if (IncludesSerializedObject)
+            {
+                ObjectInfo.Deserialize(reader);
+            }
+            else
+            {
+                ByteUnpacker.ReadValuePacked(reader, out NetworkObjectId);
+            }
+
             if (!networkManager.NetworkConfig.ForceSamePrefabs && !networkManager.SpawnManager.HasPrefab(ObjectInfo))
             {
-                networkManager.DeferredMessageManager.DeferMessage(IDeferredNetworkMessageManager.TriggerType.OnAddPrefab, ObjectInfo.Hash, reader, ref context);
+                networkManager.DeferredMessageManager.DeferMessage(IDeferredNetworkMessageManager.TriggerType.OnAddPrefab, ObjectInfo.Hash, reader, ref context, GetType().Name);
                 return false;
             }
             m_ReceivedNetworkVariableData = reader;
@@ -34,9 +172,138 @@ namespace Unity.Netcode
         public void Handle(ref NetworkContext context)
         {
             var networkManager = (NetworkManager)context.SystemOwner;
-            var networkObject = NetworkObject.AddSceneObject(ObjectInfo, m_ReceivedNetworkVariableData, networkManager);
+            // If a client receives a create object message and it is still synchronizing, then defer the object creation until it has finished synchronizing
+            if (networkManager.SceneManager.ShouldDeferCreateObject())
+            {
+                networkManager.SceneManager.DeferCreateObject(context.SenderId, context.MessageSize, ObjectInfo, m_ReceivedNetworkVariableData, ObserverIds, NewObserverIds);
+            }
+            else
+            {
+                if (networkManager.DistributedAuthorityMode && !IncludesSerializedObject && UpdateObservers)
+                {
+                    ObjectInfo = new NetworkObject.SceneObject()
+                    {
+                        NetworkObjectId = NetworkObjectId,
+                    };
+                }
+                CreateObject(ref networkManager, context.SenderId, context.MessageSize, ObjectInfo, m_ReceivedNetworkVariableData, ObserverIds, NewObserverIds);
+            }
+        }
 
-            networkManager.NetworkMetrics.TrackObjectSpawnReceived(context.SenderId, networkObject, context.MessageSize);
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        internal static void CreateObject(ref NetworkManager networkManager, ref NetworkSceneManager.DeferredObjectCreation deferredObjectCreation)
+        {
+            var senderId = deferredObjectCreation.SenderId;
+            var observerIds = deferredObjectCreation.ObserverIds;
+            var newObserverIds = deferredObjectCreation.NewObserverIds;
+            var messageSize = deferredObjectCreation.MessageSize;
+            var sceneObject = deferredObjectCreation.SceneObject;
+            var networkVariableData = deferredObjectCreation.FastBufferReader;
+            CreateObject(ref networkManager, senderId, messageSize, sceneObject, networkVariableData, observerIds, newObserverIds);
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        internal static void CreateObject(ref NetworkManager networkManager, ulong senderId, uint messageSize, NetworkObject.SceneObject sceneObject, FastBufferReader networkVariableData, ulong[] observerIds, ulong[] newObserverIds)
+        {
+            var networkObject = (NetworkObject)null;
+            try
+            {
+                if (!networkManager.DistributedAuthorityMode)
+                {
+                    networkObject = NetworkObject.AddSceneObject(sceneObject, networkVariableData, networkManager);
+                }
+                else
+                {
+                    var hasObserverIdList = observerIds != null && observerIds.Length > 0;
+                    var hasNewObserverIdList = newObserverIds != null && newObserverIds.Length > 0;
+                    // Depending upon visibility of the NetworkObject and the client in question, it could be that
+                    // this client already has visibility of this NetworkObject
+                    if (networkManager.SpawnManager.SpawnedObjects.ContainsKey(sceneObject.NetworkObjectId))
+                    {
+                        // If so, then just get the local instance
+                        networkObject = networkManager.SpawnManager.SpawnedObjects[sceneObject.NetworkObjectId];
+
+                        // This should not happen, logging error just in case
+                        if (hasNewObserverIdList && newObserverIds.Contains(networkManager.LocalClientId))
+                        {
+                            NetworkLog.LogErrorServer($"[{nameof(CreateObjectMessage)}][Duplicate-Broadcast] Detected duplicated object creation for {sceneObject.NetworkObjectId}!");
+                        }
+                        else // Trap to make sure the owner is not receiving any messages it sent
+                        if (networkManager.CMBServiceConnection && networkManager.LocalClientId == networkObject.OwnerClientId)
+                        {
+                            NetworkLog.LogWarning($"[{nameof(CreateObjectMessage)}][Client-{networkManager.LocalClientId}][Duplicate-CreateObjectMessage][Client Is Owner] Detected duplicated object creation for {networkObject.name}-{sceneObject.NetworkObjectId}!");
+                        }
+                    }
+                    else
+                    {
+                        networkObject = NetworkObject.AddSceneObject(sceneObject, networkVariableData, networkManager, true);
+                    }
+
+                    // DA - NGO CMB SERVICE NOTES:
+                    // It is possible for two clients to connect at the exact same time which, due to client-side spawning, can cause each client
+                    // to miss their spawns. For now, all player NetworkObject spawns will always be visible to all known connected clients
+                    var clientList = hasObserverIdList && !networkObject.IsPlayerObject ? observerIds : networkManager.ConnectedClientsIds;
+
+                    // Update the observers for this instance
+                    foreach (var clientId in clientList)
+                    {
+                        networkObject.Observers.Add(clientId);
+                    }
+
+                    // Mock CMB Service and forward to all clients
+                    if (networkManager.DAHost)
+                    {
+                        // DA - NGO CMB SERVICE NOTES:
+                        // (*** See above notes fist ***)
+                        // If it is a player object freshly spawning and one or more clients all connect at the exact same time (i.e. received on effectively 
+                        // the same frame), then we need to check the observers list to make sure all players are visible upon first spawning. At a later date,
+                        // for area of interest we will need to have some form of follow up "observer update" message to cull out players not within each
+                        // player's AOI.
+                        if (networkObject.IsPlayerObject && hasNewObserverIdList && clientList.Count != observerIds.Length)
+                        {
+                            // For same-frame newly spawned players that might not be aware of all other players, update the player's observer
+                            // list.
+                            observerIds = clientList.ToArray();
+                        }
+
+                        var createObjectMessage = new CreateObjectMessage()
+                        {
+                            ObjectInfo = sceneObject,
+                            m_ReceivedNetworkVariableData = networkVariableData,
+                            ObserverIds = hasObserverIdList ? observerIds : null,
+                            NetworkObjectId = networkObject.NetworkObjectId,
+                            IncludesSerializedObject = true,
+                        };
+                        foreach (var clientId in clientList)
+                        {
+                            // DA - NGO CMB SERVICE NOTES:
+                            // If the authority did not specify the list of clients and the client is not an observer or we are the owner/originator
+                            // or we are the DAHost, then we skip sending the message.
+                            if ((!hasObserverIdList && (!networkObject.Observers.Contains(clientId)) ||
+                                clientId == networkObject.OwnerClientId || clientId == NetworkManager.ServerClientId))
+                            {
+                                continue;
+                            }
+
+                            // DA - NGO CMB SERVICE NOTES:
+                            // If this included a list of new observers and the targeted clientId is one of the observers, then send the serialized data.
+                            // Otherwise, the targeted clientId has already has visibility (i.e. it is already spawned) and so just send the updated
+                            // observers list to that client's instance.
+                            createObjectMessage.IncludesSerializedObject = hasNewObserverIdList && newObserverIds.Contains(clientId);
+
+                            networkManager.SpawnManager.SendSpawnCallForObject(clientId, networkObject);
+                        }
+                    }
+                }
+                if (networkObject != null)
+                {
+                    networkManager.NetworkMetrics.TrackObjectSpawnReceived(senderId, networkObject, messageSize);
+                }
+            }
+            catch (System.Exception ex)
+            {
+                UnityEngine.Debug.LogException(ex);
+            }
         }
     }
 }

Runtime/Messaging/Messages/DestroyObjectMessage.cs

@@ -1,3 +1,5 @@
+using System.Linq;
+
 namespace Unity.Netcode
 {
     internal struct DestroyObjectMessage : INetworkMessage, INetworkSerializeByMemcpy
@@ -6,10 +8,53 @@ namespace Unity.Netcode
 
         public ulong NetworkObjectId;
         public bool DestroyGameObject;
+        private byte m_DestroyFlags;
+
+        internal int DeferredDespawnTick;
+        // Temporary until we make this a list
+        internal ulong TargetClientId;
+
+        internal bool IsDistributedAuthority;
+
+        internal const byte ClientTargetedDestroy = 0x01;
+
+        internal bool IsTargetedDestroy
+        {
+            get
+            {
+                return GetFlag(ClientTargetedDestroy);
+            }
+
+            set
+            {
+                SetFlag(value, ClientTargetedDestroy);
+            }
+        }
+
+        private bool GetFlag(int flag)
+        {
+            return (m_DestroyFlags & flag) != 0;
+        }
+
+        private void SetFlag(bool set, byte flag)
+        {
+            if (set) { m_DestroyFlags = (byte)(m_DestroyFlags | flag); }
+            else { m_DestroyFlags = (byte)(m_DestroyFlags & ~flag); }
+        }
 
         public void Serialize(FastBufferWriter writer, int targetVersion)
         {
             BytePacker.WriteValueBitPacked(writer, NetworkObjectId);
+            if (IsDistributedAuthority)
+            {
+                writer.WriteByteSafe(m_DestroyFlags);
+
+                if (IsTargetedDestroy)
+                {
+                    BytePacker.WriteValueBitPacked(writer, TargetClientId);
+                }
+                BytePacker.WriteValueBitPacked(writer, DeferredDespawnTick);
+            }
             writer.WriteValueSafe(DestroyGameObject);
         }
 
@@ -22,12 +67,25 @@ namespace Unity.Netcode
             }
 
             ByteUnpacker.ReadValueBitPacked(reader, out NetworkObjectId);
+            if (networkManager.DistributedAuthorityMode)
+            {
+                reader.ReadByteSafe(out m_DestroyFlags);
+                if (IsTargetedDestroy)
+                {
+                    ByteUnpacker.ReadValueBitPacked(reader, out TargetClientId);
+                }
+                ByteUnpacker.ReadValueBitPacked(reader, out DeferredDespawnTick);
+            }
+
             reader.ReadValueSafe(out DestroyGameObject);
 
             if (!networkManager.SpawnManager.SpawnedObjects.TryGetValue(NetworkObjectId, out var networkObject))
             {
-                networkManager.DeferredMessageManager.DeferMessage(IDeferredNetworkMessageManager.TriggerType.OnSpawn, NetworkObjectId, reader, ref context);
-                return false;
+                // Client-Server mode we always defer where in distributed authority mode we only defer if it is not a targeted destroy
+                if (!networkManager.DistributedAuthorityMode || (networkManager.DistributedAuthorityMode && !IsTargetedDestroy))
+                {
+                    networkManager.DeferredMessageManager.DeferMessage(IDeferredNetworkMessageManager.TriggerType.OnSpawn, NetworkObjectId, reader, ref context, GetType().Name);
+                }
             }
             return true;
         }
@@ -35,14 +93,80 @@ namespace Unity.Netcode
         public void Handle(ref NetworkContext context)
         {
             var networkManager = (NetworkManager)context.SystemOwner;
-            if (!networkManager.SpawnManager.SpawnedObjects.TryGetValue(NetworkObjectId, out var networkObject))
+
+            var networkObject = (NetworkObject)null;
+            if (!networkManager.DistributedAuthorityMode)
             {
-                // This is the same check and log message that happens inside OnDespawnObject, but we have to do it here
-                return;
+                // If this NetworkObject does not exist on this instance then exit early
+                if (!networkManager.SpawnManager.SpawnedObjects.TryGetValue(NetworkObjectId, out networkObject))
+                {
+                    return;
+                }
+            }
+            else
+            {
+                networkManager.SpawnManager.SpawnedObjects.TryGetValue(NetworkObjectId, out networkObject);
+                if (!networkManager.DAHost && networkObject == null)
+                {
+                    // If this NetworkObject does not exist on this instance then exit early
+                    return;
+                }
+            }
+            // DANGO-TODO: This is just a quick way to foward despawn messages to the remaining clients
+            if (networkManager.DistributedAuthorityMode && networkManager.DAHost)
+            {
+                var message = new DestroyObjectMessage
+                {
+                    NetworkObjectId = NetworkObjectId,
+                    DestroyGameObject = DestroyGameObject,
+                    IsDistributedAuthority = true,
+                    IsTargetedDestroy = IsTargetedDestroy,
+                    TargetClientId = TargetClientId, // Just always populate this value whether we write it or not
+                    DeferredDespawnTick = DeferredDespawnTick,
+                };
+                var ownerClientId = networkObject == null ? context.SenderId : networkObject.OwnerClientId;
+                var clientIds = networkObject == null ? networkManager.ConnectedClientsIds.ToList() : networkObject.Observers.ToList();
+
+                foreach (var clientId in clientIds)
+                {
+                    if (clientId == networkManager.LocalClientId || clientId == ownerClientId)
+                    {
+                        continue;
+                    }
+                    networkManager.ConnectionManager.SendMessage(ref message, NetworkDelivery.ReliableSequenced, clientId);
+                }
             }
 
-            networkManager.NetworkMetrics.TrackObjectDestroyReceived(context.SenderId, networkObject, context.MessageSize);
-            networkManager.SpawnManager.OnDespawnObject(networkObject, DestroyGameObject);
+            // If we are deferring the despawn, then add it to the deferred despawn queue
+            if (networkManager.DistributedAuthorityMode)
+            {
+                if (DeferredDespawnTick > 0)
+                {
+                    // Clients always add it to the queue while DAHost will only add it to the queue if it is not a targeted destroy or it is and the target is the
+                    // DAHost client.
+                    if (!networkManager.DAHost || (networkManager.DAHost && (!IsTargetedDestroy || (IsTargetedDestroy && TargetClientId == 0))))
+                    {
+                        networkObject.DeferredDespawnTick = DeferredDespawnTick;
+                        var hasCallback = networkObject.OnDeferredDespawnComplete != null;
+                        networkManager.SpawnManager.DeferDespawnNetworkObject(NetworkObjectId, DeferredDespawnTick, hasCallback);
+                        return;
+                    }
+                }
+
+                // If this is targeted and we are not the target, then just update our local observers for this object
+                if (IsTargetedDestroy && TargetClientId != networkManager.LocalClientId && networkObject != null)
+                {
+                    networkObject.Observers.Remove(TargetClientId);
+                    return;
+                }
+            }
+
+            if (networkObject != null)
+            {
+                // Otherwise just despawn the NetworkObject right now
+                networkManager.SpawnManager.OnDespawnObject(networkObject, DestroyGameObject);
+                networkManager.NetworkMetrics.TrackObjectDestroyReceived(context.SenderId, networkObject, context.MessageSize);
+            }
         }
     }
 }

Runtime/Messaging/Messages/NamedMessage.cs

@@ -25,9 +25,9 @@ namespace Unity.Netcode
         public void Handle(ref NetworkContext context)
         {
             var networkManager = (NetworkManager)context.SystemOwner;
-            if (!networkManager.ShutdownInProgress)
+            if (!networkManager.ShutdownInProgress && networkManager.CustomMessagingManager != null)
             {
-                ((NetworkManager)context.SystemOwner).CustomMessagingManager.InvokeNamedMessage(Hash, context.SenderId, m_ReceiveData, context.SerializedHeaderSize);
+                networkManager.CustomMessagingManager.InvokeNamedMessage(Hash, context.SenderId, m_ReceiveData, context.SerializedHeaderSize);
             }
         }
     }

Runtime/Messaging/Messages/NetworkVariableDeltaMessage.cs

@@ -23,6 +23,8 @@ namespace Unity.Netcode
 
         private FastBufferReader m_ReceivedNetworkVariableData;
 
+        // DANGO-TODO: Made some modifications here that overlap/won't play nice with EnsureNetworkVariableLenghtSafety.
+        // Worth either merging or more cleanly separating these codepaths.
         public void Serialize(FastBufferWriter writer, int targetVersion)
         {
             if (!writer.TryBeginWrite(FastBufferWriter.GetWriteSize(NetworkObjectId) + FastBufferWriter.GetWriteSize(NetworkBehaviourIndex)))
@@ -30,15 +32,26 @@ namespace Unity.Netcode
                 throw new OverflowException($"Not enough space in the buffer to write {nameof(NetworkVariableDeltaMessage)}");
             }
 
+            var obj = NetworkBehaviour.NetworkObject;
+            var networkManager = obj.NetworkManagerOwner;
+
             BytePacker.WriteValueBitPacked(writer, NetworkObjectId);
             BytePacker.WriteValueBitPacked(writer, NetworkBehaviourIndex);
+            if (networkManager.DistributedAuthorityMode)
+            {
+                writer.WriteValueSafe((ushort)NetworkBehaviour.NetworkVariableFields.Count);
+            }
 
             for (int i = 0; i < NetworkBehaviour.NetworkVariableFields.Count; i++)
             {
                 if (!DeliveryMappedNetworkVariableIndex.Contains(i))
                 {
                     // This var does not belong to the currently iterating delivery group.
-                    if (NetworkBehaviour.NetworkManager.NetworkConfig.EnsureNetworkVariableLengthSafety)
+                    if (networkManager.DistributedAuthorityMode)
+                    {
+                        writer.WriteValueSafe<ushort>(0);
+                    }
+                    else if (networkManager.NetworkConfig.EnsureNetworkVariableLengthSafety)
                     {
                         BytePacker.WriteValueBitPacked(writer, (ushort)0);
                     }
@@ -54,7 +67,7 @@ namespace Unity.Netcode
                 var networkVariable = NetworkBehaviour.NetworkVariableFields[i];
                 var shouldWrite = networkVariable.IsDirty() &&
                     networkVariable.CanClientRead(TargetClientId) &&
-                    (NetworkBehaviour.NetworkManager.IsServer || networkVariable.CanClientWrite(NetworkBehaviour.NetworkManager.LocalClientId));
+                    (networkManager.IsServer || networkVariable.CanClientWrite(networkManager.LocalClientId));
 
                 // Prevent the server from writing to the client that owns a given NetworkVariable
                 // Allowing the write would send an old value to the client and cause jitter
@@ -67,14 +80,21 @@ namespace Unity.Netcode
                 // The object containing the behaviour we're about to process is about to be shown to this client
                 // As a result, the client will get the fully serialized NetworkVariable and would be confused by
                 // an extraneous delta
-                if (NetworkBehaviour.NetworkManager.SpawnManager.ObjectsToShowToClient.ContainsKey(TargetClientId) &&
-                    NetworkBehaviour.NetworkManager.SpawnManager.ObjectsToShowToClient[TargetClientId]
-                    .Contains(NetworkBehaviour.NetworkObject))
+                if (networkManager.SpawnManager.ObjectsToShowToClient.ContainsKey(TargetClientId) &&
+                    networkManager.SpawnManager.ObjectsToShowToClient[TargetClientId]
+                    .Contains(obj))
                 {
                     shouldWrite = false;
                 }
 
-                if (NetworkBehaviour.NetworkManager.NetworkConfig.EnsureNetworkVariableLengthSafety)
+                if (networkManager.DistributedAuthorityMode)
+                {
+                    if (!shouldWrite)
+                    {
+                        writer.WriteValueSafe<ushort>(0);
+                    }
+                }
+                else if (networkManager.NetworkConfig.EnsureNetworkVariableLengthSafety)
                 {
                     if (!shouldWrite)
                     {
@@ -88,9 +108,9 @@ namespace Unity.Netcode
 
                 if (shouldWrite)
                 {
-                    if (NetworkBehaviour.NetworkManager.NetworkConfig.EnsureNetworkVariableLengthSafety)
+                    if (networkManager.NetworkConfig.EnsureNetworkVariableLengthSafety)
                     {
-                        var tempWriter = new FastBufferWriter(NetworkBehaviour.NetworkManager.MessageManager.NonFragmentedMessageMaxSize, Allocator.Temp, NetworkBehaviour.NetworkManager.MessageManager.FragmentedMessageMaxSize);
+                        var tempWriter = new FastBufferWriter(networkManager.MessageManager.NonFragmentedMessageMaxSize, Allocator.Temp, networkManager.MessageManager.FragmentedMessageMaxSize);
                         NetworkBehaviour.NetworkVariableFields[i].WriteDelta(tempWriter);
                         BytePacker.WriteValueBitPacked(writer, tempWriter.Length);
 
@@ -103,11 +123,30 @@ namespace Unity.Netcode
                     }
                     else
                     {
-                        networkVariable.WriteDelta(writer);
+                        // DANGO-TODO:
+                        // Complex types with custom type serialization (either registered custom types or INetworkSerializable implementations) will be problematic
+                        // Non-complex types always provide a full state update per delta
+                        // DANGO-TODO: Add NetworkListEvent<T>.EventType awareness to the cloud-state server
+                        if (networkManager.DistributedAuthorityMode)
+                        {
+                            var size_marker = writer.Position;
+                            writer.WriteValueSafe<ushort>(0);
+                            var start_marker = writer.Position;
+                            networkVariable.WriteDelta(writer);
+                            var end_marker = writer.Position;
+                            writer.Seek(size_marker);
+                            var size = end_marker - start_marker;
+                            writer.WriteValueSafe((ushort)size);
+                            writer.Seek(end_marker);
+                        }
+                        else
+                        {
+                            networkVariable.WriteDelta(writer);
+                        }
                     }
-                    NetworkBehaviour.NetworkManager.NetworkMetrics.TrackNetworkVariableDeltaSent(
+                    networkManager.NetworkMetrics.TrackNetworkVariableDeltaSent(
                         TargetClientId,
-                        NetworkBehaviour.NetworkObject,
+                        obj,
                         networkVariable.Name,
                         NetworkBehaviour.__getTypeName(),
                         writer.Length - startingSize);
@@ -125,6 +164,8 @@ namespace Unity.Netcode
             return true;
         }
 
+        // DANGO-TODO: Made some modifications here that overlap/won't play nice with EnsureNetworkVariableLenghtSafety.
+        // Worth either merging or more cleanly separating these codepaths.
         public void Handle(ref NetworkContext context)
         {
             var networkManager = (NetworkManager)context.SystemOwner;
@@ -142,10 +183,29 @@ namespace Unity.Netcode
                 }
                 else
                 {
+                    if (networkManager.DistributedAuthorityMode)
+                    {
+                        m_ReceivedNetworkVariableData.ReadValueSafe(out ushort variableCount);
+                        if (variableCount != networkBehaviour.NetworkVariableFields.Count)
+                        {
+                            UnityEngine.Debug.LogError("Variable count mismatch");
+                        }
+                    }
+
                     for (int i = 0; i < networkBehaviour.NetworkVariableFields.Count; i++)
                     {
                         int varSize = 0;
-                        if (networkManager.NetworkConfig.EnsureNetworkVariableLengthSafety)
+                        if (networkManager.DistributedAuthorityMode)
+                        {
+                            m_ReceivedNetworkVariableData.ReadValueSafe(out ushort variableSize);
+                            varSize = variableSize;
+
+                            if (varSize == 0)
+                            {
+                                continue;
+                            }
+                        }
+                        else if (networkManager.NetworkConfig.EnsureNetworkVariableLengthSafety)
                         {
                             ByteUnpacker.ReadValueBitPacked(m_ReceivedNetworkVariableData, out varSize);
 
@@ -197,6 +257,7 @@ namespace Unity.Netcode
                         }
                         int readStartPos = m_ReceivedNetworkVariableData.Position;
 
+                        // Read Delta so we also notify any subscribers to a change in the NetworkVariable
                         networkVariable.ReadDelta(m_ReceivedNetworkVariableData, networkManager.IsServer);
 
                         networkManager.NetworkMetrics.TrackNetworkVariableDeltaReceived(
@@ -206,7 +267,7 @@ namespace Unity.Netcode
                             networkBehaviour.__getTypeName(),
                             context.MessageSize);
 
-                        if (networkManager.NetworkConfig.EnsureNetworkVariableLengthSafety)
+                        if (networkManager.NetworkConfig.EnsureNetworkVariableLengthSafety || networkManager.DistributedAuthorityMode)
                         {
                             if (m_ReceivedNetworkVariableData.Position > (readStartPos + varSize))
                             {
@@ -232,7 +293,10 @@ namespace Unity.Netcode
             }
             else
             {
-                networkManager.DeferredMessageManager.DeferMessage(IDeferredNetworkMessageManager.TriggerType.OnSpawn, NetworkObjectId, m_ReceivedNetworkVariableData, ref context);
+                // DANGO-TODO: Fix me!
+                // When a client-spawned NetworkObject is despawned by the owner client, the owner client will still get messages for deltas and cause this to
+                // log a warning. The issue is primarily how NetworkVariables handle updating and will require some additional re-factoring.
+                networkManager.DeferredMessageManager.DeferMessage(IDeferredNetworkMessageManager.TriggerType.OnSpawn, NetworkObjectId, m_ReceivedNetworkVariableData, ref context, GetType().Name);
             }
         }
     }

Runtime/Messaging/Messages/ParentSyncMessage.cs

@@ -33,6 +33,12 @@ namespace Unity.Netcode
             set => ByteUtility.SetBit(ref m_BitField, 2, value);
         }
 
+        public bool AuthorityApplied
+        {
+            get => ByteUtility.GetBit(m_BitField, 3);
+            set => ByteUtility.SetBit(ref m_BitField, 3, value);
+        }
+
         // These additional properties are used to synchronize clients with the current position,
         // rotation, and scale after parenting/de-parenting (world/local space relative). This
         // allows users to control the final child's transform values without having to have a
@@ -83,9 +89,10 @@ namespace Unity.Netcode
             reader.ReadValueSafe(out Rotation);
             reader.ReadValueSafe(out Scale);
 
-            if (!networkManager.SpawnManager.SpawnedObjects.ContainsKey(NetworkObjectId))
+            // If the target NetworkObject does not exist =or= the target latest parent does not exist then defer the message
+            if (!networkManager.SpawnManager.SpawnedObjects.ContainsKey(NetworkObjectId) || (LatestParent.HasValue && !networkManager.SpawnManager.SpawnedObjects.ContainsKey(LatestParent.Value)))
             {
-                networkManager.DeferredMessageManager.DeferMessage(IDeferredNetworkMessageManager.TriggerType.OnSpawn, NetworkObjectId, reader, ref context);
+                networkManager.DeferredMessageManager.DeferMessage(IDeferredNetworkMessageManager.TriggerType.OnSpawn, NetworkObjectId, reader, ref context, GetType().Name);
                 return false;
             }
             return true;
@@ -95,6 +102,16 @@ namespace Unity.Netcode
         {
             var networkManager = (NetworkManager)context.SystemOwner;
             var networkObject = networkManager.SpawnManager.SpawnedObjects[NetworkObjectId];
+
+            // For either DA or Client-Server modes, parenting is only valid if the parent was owned by a different authority (i.e. AuthorityApplied) or the sender is from the owner (DA mode)
+            // or the server (client-server mode).
+            networkObject.AuthorityAppliedParenting = AuthorityApplied || context.SenderId == networkObject.OwnerClientId || context.SenderId == NetworkManager.ServerClientId;
+            if (!networkObject.AuthorityAppliedParenting && networkManager.LogLevel <= LogLevel.Normal)
+            {
+                NetworkLog.LogWarningServer($"Client-{context.SenderId} sent a ParentSyncMessage but is not the authority of {networkObject.gameObject.name}'s {nameof(NetworkObject)} component!");
+                // DANGO-TODO: Still determining if we should not apply this change (I am leaning towards not allowing it).
+            }
+
             networkObject.SetNetworkParenting(LatestParent, WorldPositionStays);
             networkObject.ApplyNetworkParenting(RemoveParent);
 
@@ -111,6 +128,30 @@ namespace Unity.Netcode
                 networkObject.transform.rotation = Rotation;
             }
             networkObject.transform.localScale = Scale;
+
+            // If in distributed authority mode and we are running a DAHost and this is the DAHost, then forward the parent changed message to any remaining clients
+            if (networkManager.DistributedAuthorityMode && !networkManager.CMBServiceConnection && networkManager.DAHost)
+            {
+                var size = 0;
+                var message = this;
+
+                foreach (var client in networkManager.ConnectedClients)
+                {
+                    if (client.Value.ClientId == networkObject.OwnerClientId || client.Value.ClientId == networkManager.LocalClientId)
+                    {
+                        continue;
+                    }
+                    if (networkObject.IsNetworkVisibleTo(client.Value.ClientId))
+                    {
+                        size = networkManager.ConnectionManager.SendMessage(ref message, NetworkDelivery.ReliableSequenced, client.Value.ClientId);
+                        networkManager.NetworkMetrics.TrackOwnershipChangeSent(client.Key, networkObject, size);
+                    }
+                    else
+                    {
+                        Debug.Log($"[DAHost][ParentingProxy] Client-{client.Value.ClientId} has no visibility to {networkObject.name}!");
+                    }
+                }
+            }
         }
     }
 }

Runtime/Messaging/Messages/ProxyMessage.cs

@@ -0,0 +1,83 @@
+using System;
+using Unity.Collections;
+
+namespace Unity.Netcode
+{
+    internal struct ProxyMessage : INetworkMessage
+    {
+        public NativeArray<ulong> TargetClientIds;
+        public NetworkDelivery Delivery;
+        public RpcMessage WrappedMessage;
+
+        // Version of ProxyMessage and RpcMessage must always match.
+        // If ProxyMessage needs to change, increment RpcMessage's version
+        public int Version => new RpcMessage().Version;
+
+        public void Serialize(FastBufferWriter writer, int targetVersion)
+        {
+            writer.WriteValueSafe(TargetClientIds);
+            BytePacker.WriteValuePacked(writer, Delivery);
+            WrappedMessage.Serialize(writer, targetVersion);
+        }
+
+        public bool Deserialize(FastBufferReader reader, ref NetworkContext context, int receivedMessageVersion)
+        {
+            reader.ReadValueSafe(out TargetClientIds, Allocator.Temp);
+            ByteUnpacker.ReadValuePacked(reader, out Delivery);
+            WrappedMessage = new RpcMessage();
+            WrappedMessage.Deserialize(reader, ref context, receivedMessageVersion);
+            return true;
+        }
+
+        public unsafe void Handle(ref NetworkContext context)
+        {
+            var networkManager = (NetworkManager)context.SystemOwner;
+            if (!networkManager.SpawnManager.SpawnedObjects.TryGetValue(WrappedMessage.Metadata.NetworkObjectId, out var networkObject))
+            {
+                // With distributed authority mode, we can send Rpcs before we have been notified the NetworkObject is despawned.
+                // DANGO-TODO: Should the CMB Service cull out any Rpcs targeting recently despawned NetworkObjects?
+                // DANGO-TODO: This would require the service to keep track of despawned NetworkObjects since we re-use NetworkObject identifiers.
+                if (networkManager.DistributedAuthorityMode)
+                {
+                    if (networkManager.LogLevel == LogLevel.Developer)
+                    {
+                        NetworkLog.LogWarning($"[{WrappedMessage.Metadata.NetworkObjectId}, {WrappedMessage.Metadata.NetworkBehaviourId}, {WrappedMessage.Metadata.NetworkRpcMethodId}]An RPC called on a {nameof(NetworkObject)} that is not in the spawned objects list. Please make sure the {nameof(NetworkObject)} is spawned before calling RPCs.");
+                    }
+                    return;
+                }
+                else
+                {
+                    throw new InvalidOperationException($"[{WrappedMessage.Metadata.NetworkObjectId}, {WrappedMessage.Metadata.NetworkBehaviourId}, {WrappedMessage.Metadata.NetworkRpcMethodId}]An RPC called on a {nameof(NetworkObject)} that is not in the spawned objects list. Please make sure the {nameof(NetworkObject)} is spawned before calling RPCs.");
+                }
+            }
+
+            var observers = networkObject.Observers;
+
+            var nonServerIds = new NativeList<ulong>(Allocator.Temp);
+            for (var i = 0; i < TargetClientIds.Length; ++i)
+            {
+                if (!observers.Contains(TargetClientIds[i]))
+                {
+                    continue;
+                }
+
+                if (TargetClientIds[i] == NetworkManager.ServerClientId)
+                {
+                    WrappedMessage.Handle(ref context);
+                }
+                else
+                {
+                    nonServerIds.Add(TargetClientIds[i]);
+                }
+            }
+
+            WrappedMessage.WriteBuffer = new FastBufferWriter(WrappedMessage.ReadBuffer.Length, Allocator.Temp);
+
+            using (WrappedMessage.WriteBuffer)
+            {
+                WrappedMessage.WriteBuffer.WriteBytesSafe(WrappedMessage.ReadBuffer.GetUnsafePtr(), WrappedMessage.ReadBuffer.Length);
+                networkManager.MessageManager.SendMessage(ref WrappedMessage, Delivery, nonServerIds);
+            }
+        }
+    }
+}

Runtime/Messaging/Messages/ProxyMessage.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: e9ee0457d5b740b38dfe6542658fb522
+timeCreated: 1697825043

Runtime/Messaging/Messages/RpcMessages.cs

@@ -14,7 +14,7 @@ namespace Unity.Netcode
             writer.WriteBytesSafe(payload.GetUnsafePtr(), payload.Length);
         }
 
-        public static unsafe bool Deserialize(ref FastBufferReader reader, ref NetworkContext context, ref RpcMetadata metadata, ref FastBufferReader payload)
+        public static unsafe bool Deserialize(ref FastBufferReader reader, ref NetworkContext context, ref RpcMetadata metadata, ref FastBufferReader payload, string messageType)
         {
             ByteUnpacker.ReadValueBitPacked(reader, out metadata.NetworkObjectId);
             ByteUnpacker.ReadValueBitPacked(reader, out metadata.NetworkBehaviourId);
@@ -23,7 +23,7 @@ namespace Unity.Netcode
             var networkManager = (NetworkManager)context.SystemOwner;
             if (!networkManager.SpawnManager.SpawnedObjects.ContainsKey(metadata.NetworkObjectId))
             {
-                networkManager.DeferredMessageManager.DeferMessage(IDeferredNetworkMessageManager.TriggerType.OnSpawn, metadata.NetworkObjectId, reader, ref context);
+                networkManager.DeferredMessageManager.DeferMessage(IDeferredNetworkMessageManager.TriggerType.OnSpawn, metadata.NetworkObjectId, reader, ref context, messageType);
                 return false;
             }
 
@@ -52,7 +52,6 @@ namespace Unity.Netcode
                     reader.Length);
             }
 #endif
-
             return true;
         }
 
@@ -107,7 +106,7 @@ namespace Unity.Netcode
 
         public unsafe bool Deserialize(FastBufferReader reader, ref NetworkContext context, int receivedMessageVersion)
         {
-            return RpcMessageHelpers.Deserialize(ref reader, ref context, ref Metadata, ref ReadBuffer);
+            return RpcMessageHelpers.Deserialize(ref reader, ref context, ref Metadata, ref ReadBuffer, GetType().Name);
         }
 
         public void Handle(ref NetworkContext context)
@@ -142,7 +141,7 @@ namespace Unity.Netcode
 
         public bool Deserialize(FastBufferReader reader, ref NetworkContext context, int receivedMessageVersion)
         {
-            return RpcMessageHelpers.Deserialize(ref reader, ref context, ref Metadata, ref ReadBuffer);
+            return RpcMessageHelpers.Deserialize(ref reader, ref context, ref Metadata, ref ReadBuffer, GetType().Name);
         }
 
         public void Handle(ref NetworkContext context)
@@ -159,4 +158,177 @@ namespace Unity.Netcode
             RpcMessageHelpers.Handle(ref context, ref Metadata, ref ReadBuffer, ref rpcParams);
         }
     }
+
+    internal struct RpcMessage : INetworkMessage
+    {
+        public int Version => 0;
+
+        public RpcMetadata Metadata;
+        public ulong SenderClientId;
+
+        public FastBufferWriter WriteBuffer;
+        public FastBufferReader ReadBuffer;
+
+        public unsafe void Serialize(FastBufferWriter writer, int targetVersion)
+        {
+            BytePacker.WriteValuePacked(writer, SenderClientId);
+            RpcMessageHelpers.Serialize(ref writer, ref Metadata, ref WriteBuffer);
+        }
+
+        public unsafe bool Deserialize(FastBufferReader reader, ref NetworkContext context, int receivedMessageVersion)
+        {
+            ByteUnpacker.ReadValuePacked(reader, out SenderClientId);
+
+            return RpcMessageHelpers.Deserialize(ref reader, ref context, ref Metadata, ref ReadBuffer, GetType().Name);
+        }
+
+        public void Handle(ref NetworkContext context)
+        {
+            var rpcParams = new __RpcParams
+            {
+                Ext = new RpcParams
+                {
+                    Receive = new RpcReceiveParams
+                    {
+                        SenderClientId = SenderClientId
+                    }
+                }
+            };
+            RpcMessageHelpers.Handle(ref context, ref Metadata, ref ReadBuffer, ref rpcParams);
+        }
+    }
+
+    // DANGO-EXP TODO: REMOVE THIS
+    internal struct ForwardServerRpcMessage : INetworkMessage
+    {
+        public int Version => 0;
+        public ulong OwnerId;
+        public NetworkDelivery NetworkDelivery;
+        public ServerRpcMessage ServerRpcMessage;
+
+        public unsafe void Serialize(FastBufferWriter writer, int targetVersion)
+        {
+            writer.WriteValueSafe(OwnerId);
+            writer.WriteValueSafe(NetworkDelivery);
+            ServerRpcMessage.Serialize(writer, targetVersion);
+        }
+
+        public unsafe bool Deserialize(FastBufferReader reader, ref NetworkContext context, int receivedMessageVersion)
+        {
+            reader.ReadValueSafe(out OwnerId);
+            reader.ReadValueSafe(out NetworkDelivery);
+            ServerRpcMessage.ReadBuffer = new FastBufferReader(reader, Allocator.Persistent, reader.Length - reader.Position, sizeof(RpcMetadata));
+
+            // If deserializing failed or this message was deferred.
+            if (!ServerRpcMessage.Deserialize(reader, ref context, receivedMessageVersion))
+            {
+                // release this reader as the handler will either be invoked later (deferred) or will not be invoked at all.
+                ServerRpcMessage.ReadBuffer.Dispose();
+                return false;
+            }
+            return true;
+        }
+
+        public void Handle(ref NetworkContext context)
+        {
+            var networkManager = (NetworkManager)context.SystemOwner;
+            if (networkManager.DAHost)
+            {
+                try
+                {
+                    // Since this is temporary, we will not be collection metrics for this.
+                    // DAHost just forwards the message to the owner
+                    ServerRpcMessage.WriteBuffer = new FastBufferWriter(ServerRpcMessage.ReadBuffer.Length, Allocator.TempJob);
+                    ServerRpcMessage.WriteBuffer.WriteBytesSafe(ServerRpcMessage.ReadBuffer.ToArray());
+                    networkManager.ConnectionManager.SendMessage(ref ServerRpcMessage, NetworkDelivery, OwnerId);
+                }
+                catch (Exception ex)
+                {
+                    Debug.LogException(ex);
+                }
+            }
+            else
+            {
+                NetworkLog.LogErrorServer($"Received {nameof(ForwardServerRpcMessage)} on client-{networkManager.LocalClientId}! Only DAHost may forward RPC messages!");
+            }
+            ServerRpcMessage.ReadBuffer.Dispose();
+            ServerRpcMessage.WriteBuffer.Dispose();
+        }
+
+    }
+
+    // DANGO-EXP TODO: REMOVE THIS
+    internal struct ForwardClientRpcMessage : INetworkMessage
+    {
+        public int Version => 0;
+        public bool BroadCast;
+        public ulong[] TargetClientIds;
+        public NetworkDelivery NetworkDelivery;
+        public ClientRpcMessage ClientRpcMessage;
+
+        public unsafe void Serialize(FastBufferWriter writer, int targetVersion)
+        {
+            if (TargetClientIds == null)
+            {
+                BroadCast = true;
+                writer.WriteValueSafe(BroadCast);
+            }
+            else
+            {
+                BroadCast = false;
+                writer.WriteValueSafe(BroadCast);
+                writer.WriteValueSafe(TargetClientIds);
+            }
+            writer.WriteValueSafe(NetworkDelivery);
+            ClientRpcMessage.Serialize(writer, targetVersion);
+        }
+
+        public unsafe bool Deserialize(FastBufferReader reader, ref NetworkContext context, int receivedMessageVersion)
+        {
+            reader.ReadValueSafe(out BroadCast);
+
+            if (!BroadCast)
+            {
+                reader.ReadValueSafe(out TargetClientIds);
+            }
+
+            reader.ReadValueSafe(out NetworkDelivery);
+
+            ClientRpcMessage.ReadBuffer = new FastBufferReader(reader, Allocator.Persistent, reader.Length - reader.Position, sizeof(RpcMetadata));
+            // If deserializing failed or this message was deferred.
+            if (!ClientRpcMessage.Deserialize(reader, ref context, receivedMessageVersion))
+            {
+                // release this reader as the handler will either be invoked later (deferred) or will not be invoked at all.
+                ClientRpcMessage.ReadBuffer.Dispose();
+                return false;
+            }
+            return true;
+        }
+
+        public void Handle(ref NetworkContext context)
+        {
+            var networkManager = (NetworkManager)context.SystemOwner;
+            if (networkManager.DAHost)
+            {
+                ClientRpcMessage.WriteBuffer = new FastBufferWriter(ClientRpcMessage.ReadBuffer.Length, Allocator.TempJob);
+                ClientRpcMessage.WriteBuffer.WriteBytesSafe(ClientRpcMessage.ReadBuffer.ToArray());
+                // Since this is temporary, we will not be collection metrics for this.
+                // DAHost just forwards the message to the clients
+                if (BroadCast)
+                {
+                    networkManager.ConnectionManager.SendMessage(ref ClientRpcMessage, NetworkDelivery, networkManager.ConnectedClientsIds);
+                }
+                else
+                {
+                    networkManager.ConnectionManager.SendMessage(ref ClientRpcMessage, NetworkDelivery, TargetClientIds);
+                }
+            }
+            else
+            {
+                NetworkLog.LogErrorServer($"Received {nameof(ForwardClientRpcMessage)} on client-{networkManager.LocalClientId}! Only DAHost may forward RPC messages!");
+            }
+            ClientRpcMessage.WriteBuffer.Dispose();
+            ClientRpcMessage.ReadBuffer.Dispose();
+        }
+    }
 }

Runtime/Messaging/Messages/SceneEventMessage.cs

@@ -1,3 +1,4 @@
+
 namespace Unity.Netcode
 {
     // Todo: Would be lovely to get this one nicely formatted with all the data it sends in the struct
@@ -8,6 +9,7 @@ namespace Unity.Netcode
 
         public SceneEventData EventData;
 
+
         private FastBufferReader m_ReceivedData;
 
         public void Serialize(FastBufferWriter writer, int targetVersion)
@@ -23,7 +25,8 @@ namespace Unity.Netcode
 
         public void Handle(ref NetworkContext context)
         {
-            ((NetworkManager)context.SystemOwner).SceneManager.HandleSceneEvent(context.SenderId, m_ReceivedData);
+            var networkManager = (NetworkManager)context.SystemOwner;
+            networkManager.SceneManager.HandleSceneEvent(context.SenderId, m_ReceivedData);
         }
     }
 }

Runtime/Messaging/Messages/ServerLogMessage.cs

@@ -4,6 +4,8 @@ namespace Unity.Netcode
     {
         public int Version => 0;
 
+        public ulong SenderId;
+
         public NetworkLog.LogType LogType;
         // It'd be lovely to be able to replace this with FixedString or NativeArray...
         // But it's not really practical. On the sending side, the user is likely to want
@@ -12,30 +14,39 @@ namespace Unity.Netcode
         // So an allocation is unavoidable here on both sides.
         public string Message;
 
-
         public void Serialize(FastBufferWriter writer, int targetVersion)
         {
             writer.WriteValueSafe(LogType);
             BytePacker.WriteValuePacked(writer, Message);
+            BytePacker.WriteValueBitPacked(writer, SenderId);
         }
 
         public bool Deserialize(FastBufferReader reader, ref NetworkContext context, int receivedMessageVersion)
         {
             var networkManager = (NetworkManager)context.SystemOwner;
-            if (networkManager.IsServer && networkManager.NetworkConfig.EnableNetworkLogs)
+
+            if ((networkManager.IsServer || networkManager.LocalClient.IsSessionOwner) && networkManager.NetworkConfig.EnableNetworkLogs)
             {
                 reader.ReadValueSafe(out LogType);
                 ByteUnpacker.ReadValuePacked(reader, out Message);
+                ByteUnpacker.ReadValuePacked(reader, out SenderId);
+                // If in distributed authority mode and the DAHost is not the session owner, then the DAHost will just forward the message.
+                if (networkManager.DAHost && networkManager.CurrentSessionOwner != networkManager.LocalClientId)
+                {
+                    var message = this;
+                    var size = networkManager.ConnectionManager.SendMessage(ref message, NetworkDelivery.ReliableFragmentedSequenced, networkManager.CurrentSessionOwner);
+                    networkManager.NetworkMetrics.TrackServerLogSent(networkManager.CurrentSessionOwner, (uint)LogType, size);
+                    return false;
+                }
                 return true;
             }
-
             return false;
         }
 
         public void Handle(ref NetworkContext context)
         {
             var networkManager = (NetworkManager)context.SystemOwner;
-            var senderId = context.SenderId;
+            var senderId = networkManager.DistributedAuthorityMode ? SenderId : context.SenderId;
 
             networkManager.NetworkMetrics.TrackServerLogReceived(senderId, (uint)LogType, context.MessageSize);
 

Runtime/Messaging/Messages/SessionOwnerMessage.cs

@@ -0,0 +1,26 @@
+namespace Unity.Netcode
+{
+    internal struct SessionOwnerMessage : INetworkMessage
+    {
+        public int Version => 0;
+
+        public ulong SessionOwner;
+
+        public void Serialize(FastBufferWriter writer, int targetVersion)
+        {
+            BytePacker.WriteValuePacked(writer, SessionOwner);
+        }
+
+        public bool Deserialize(FastBufferReader reader, ref NetworkContext context, int receivedMessageVersion)
+        {
+            ByteUnpacker.ReadValuePacked(reader, out SessionOwner);
+            return true;
+        }
+
+        public unsafe void Handle(ref NetworkContext context)
+        {
+            var networkManager = (NetworkManager)context.SystemOwner;
+            networkManager.SetSessionOwner(SessionOwner);
+        }
+    }
+}

Runtime/Messaging/Messages/SessionOwnerMessage.cs.meta

@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 8e02985965397ab44809c99406914311
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Runtime/Messaging/NetworkManagerHooks.cs

@@ -1,4 +1,5 @@
 using System;
+using Unity.Netcode.Transports.UTP;
 
 namespace Unity.Netcode
 {
@@ -56,7 +57,8 @@ namespace Unity.Netcode
                 {
                     if (NetworkLog.CurrentLogLevel <= LogLevel.Normal)
                     {
-                        NetworkLog.LogError($"A {nameof(ConnectionApprovedMessage)} was received from a client on the server side. This should not happen. Please report this to the Netcode for GameObjects team at https://github.com/Unity-Technologies/com.unity.netcode.gameobjects/issues and include the following data: Message Size: {messageContent.Length}. Message Content: {NetworkMessageManager.ByteArrayToString(messageContent.ToArray(), 0, messageContent.Length)}");
+                        var transportErrorMsg = GetTransportErrorMessage(messageContent, m_NetworkManager);
+                        NetworkLog.LogError($"A {nameof(ConnectionApprovedMessage)} was received from a client on the server side. {transportErrorMsg}");
                     }
 
                     return false;
@@ -66,7 +68,7 @@ namespace Unity.Netcode
                 {
                     if (NetworkLog.CurrentLogLevel <= LogLevel.Normal)
                     {
-                        NetworkLog.LogWarning($"Message received from {nameof(senderId)}={senderId} before it has been accepted");
+                        NetworkLog.LogWarning($"Message received from {nameof(senderId)}={senderId} before it has been accepted.");
                     }
 
                     return false;
@@ -76,7 +78,8 @@ namespace Unity.Netcode
                 {
                     if (NetworkLog.CurrentLogLevel <= LogLevel.Normal)
                     {
-                        NetworkLog.LogError($"A {nameof(ConnectionRequestMessage)} was received from a client when the connection has already been established. This should not happen. Please report this to the Netcode for GameObjects team at https://github.com/Unity-Technologies/com.unity.netcode.gameobjects/issues and include the following data: Message Size: {messageContent.Length}. Message Content: {NetworkMessageManager.ByteArrayToString(messageContent.ToArray(), 0, messageContent.Length)}");
+                        var transportErrorMsg = GetTransportErrorMessage(messageContent, m_NetworkManager);
+                        NetworkLog.LogError($"A {nameof(ConnectionRequestMessage)} was received from a client when the connection has already been established. {transportErrorMsg}");
                     }
 
                     return false;
@@ -88,7 +91,8 @@ namespace Unity.Netcode
                 {
                     if (NetworkLog.CurrentLogLevel <= LogLevel.Normal)
                     {
-                        NetworkLog.LogError($"A {nameof(ConnectionRequestMessage)} was received from the server on the client side. This should not happen. Please report this to the Netcode for GameObjects team at https://github.com/Unity-Technologies/com.unity.netcode.gameobjects/issues and include the following data: Message Size: {messageContent.Length}. Message Content: {NetworkMessageManager.ByteArrayToString(messageContent.ToArray(), 0, messageContent.Length)}");
+                        var transportErrorMsg = GetTransportErrorMessage(messageContent, m_NetworkManager);
+                        NetworkLog.LogError($"A {nameof(ConnectionRequestMessage)} was received from the server on the client side. {transportErrorMsg}");
                     }
 
                     return false;
@@ -98,7 +102,8 @@ namespace Unity.Netcode
                 {
                     if (NetworkLog.CurrentLogLevel <= LogLevel.Normal)
                     {
-                        NetworkLog.LogError($"A {nameof(ConnectionApprovedMessage)} was received from the server when the connection has already been established. This should not happen. Please report this to the Netcode for GameObjects team at https://github.com/Unity-Technologies/com.unity.netcode.gameobjects/issues and include the following data: Message Size: {messageContent.Length}. Message Content: {NetworkMessageManager.ByteArrayToString(messageContent.ToArray(), 0, messageContent.Length)}");
+                        var transportErrorMsg = GetTransportErrorMessage(messageContent, m_NetworkManager);
+                        NetworkLog.LogError($"A {nameof(ConnectionApprovedMessage)} was received from the server when the connection has already been established. {transportErrorMsg}");
                     }
 
                     return false;
@@ -108,6 +113,28 @@ namespace Unity.Netcode
             return !m_NetworkManager.MessageManager.StopProcessing;
         }
 
+        private static string GetTransportErrorMessage(FastBufferReader messageContent, NetworkManager networkManager)
+        {
+            if (networkManager.NetworkConfig.NetworkTransport is not UnityTransport)
+            {
+                return $"NetworkTransport: {networkManager.NetworkConfig.NetworkTransport.GetType()}. Please report this to the maintainer of transport layer.";
+            }
+
+            var transportVersion = GetTransportVersion(networkManager);
+            return $"{transportVersion}. This should not happen. Please report this to the Netcode for GameObjects team at https://github.com/Unity-Technologies/com.unity.netcode.gameobjects/issues and include the following data: Message Size: {messageContent.Length}. Message Content: {NetworkMessageManager.ByteArrayToString(messageContent.ToArray(), 0, messageContent.Length)}";
+        }
+
+        private static string GetTransportVersion(NetworkManager networkManager)
+        {
+            var transportVersion = "NetworkTransport: " + networkManager.NetworkConfig.NetworkTransport.GetType();
+            if (networkManager.NetworkConfig.NetworkTransport is UnityTransport unityTransport)
+            {
+                transportVersion += " UnityTransportProtocol: " + unityTransport.Protocol;
+            }
+
+            return transportVersion;
+        }
+
         public void OnBeforeHandleMessage<T>(ref T message, ref NetworkContext context) where T : INetworkMessage
         {
         }

Runtime/Messaging/NetworkMessageManager.cs

@@ -85,6 +85,8 @@ namespace Unity.Netcode
         private INetworkMessageSender m_Sender;
         private bool m_Disposed;
 
+        private ulong m_LocalClientId;
+
         internal Type[] MessageTypes => m_ReverseTypeMap;
         internal MessageHandler[] MessageHandlers => m_MessageHandlers;
 
@@ -95,6 +97,16 @@ namespace Unity.Netcode
             return m_MessageTypes[t];
         }
 
+        internal object GetOwner()
+        {
+            return m_Owner;
+        }
+
+        internal void SetLocalClientId(ulong id)
+        {
+            m_LocalClientId = id;
+        }
+
         public const int DefaultNonFragmentedMessageMaxSize = 1300 & ~7; // Round down to nearest word aligned size (1296)
         public int NonFragmentedMessageMaxSize = DefaultNonFragmentedMessageMaxSize;
         public int FragmentedMessageMaxSize = int.MaxValue;
@@ -155,6 +167,28 @@ namespace Unity.Netcode
                 {
                     RegisterMessageType(type);
                 }
+
+#if UNITY_EDITOR
+                if (EnableMessageOrderConsoleLog)
+                {
+                    // DANGO-TODO: Remove this when we have some form of message type indices stability in place
+                    // For now, just log the messages and their assigned types for reference purposes.
+                    var networkManager = m_Owner as NetworkManager;
+                    if (networkManager != null)
+                    {
+                        if (networkManager.DistributedAuthorityMode)
+                        {
+                            var messageListing = new StringBuilder();
+                            messageListing.AppendLine("NGO Message Index to Type Listing:");
+                            foreach (var message in m_MessageTypes)
+                            {
+                                messageListing.AppendLine($"[{message.Value}][{message.Key.Name}]");
+                            }
+                            Debug.Log(messageListing);
+                        }
+                    }
+                }
+#endif
             }
             catch (Exception)
             {
@@ -163,6 +197,8 @@ namespace Unity.Netcode
             }
         }
 
+        internal static bool EnableMessageOrderConsoleLog = false;
+
         public void Dispose()
         {
             if (m_Disposed)
@@ -551,7 +587,7 @@ namespace Unity.Netcode
             // Special cases because these are the messages that carry the version info - thus the version info isn't
             // populated yet when we get these. The first part of these messages always has to be the version data
             // and can't change.
-            if (typeof(T) != typeof(ConnectionRequestMessage) && typeof(T) != typeof(ConnectionApprovedMessage) && typeof(T) != typeof(DisconnectReasonMessage))
+            if (typeof(T) != typeof(ConnectionRequestMessage) && typeof(T) != typeof(ConnectionApprovedMessage) && typeof(T) != typeof(DisconnectReasonMessage) && context.SenderId != manager.m_LocalClientId)
             {
                 messageVersion = manager.GetMessageVersion(typeof(T), context.SenderId, true);
                 if (messageVersion < 0)
@@ -808,6 +844,16 @@ namespace Unity.Netcode
             return SendMessage(ref message, delivery, new PointerListWrapper<ulong>((ulong*)clientIds.GetUnsafePtr(), clientIds.Length));
         }
 
+        internal unsafe int SendMessage<T>(ref T message, NetworkDelivery delivery, in NativeList<ulong> clientIds)
+            where T : INetworkMessage
+        {
+#if UTP_TRANSPORT_2_0_ABOVE
+            return SendMessage(ref message, delivery, new PointerListWrapper<ulong>(clientIds.GetUnsafePtr(), clientIds.Length));
+#else
+            return SendMessage(ref message, delivery, new PointerListWrapper<ulong>((ulong*)clientIds.GetUnsafePtr(), clientIds.Length));
+#endif
+        }
+
         internal unsafe void ProcessSendQueues()
         {
             if (StopProcessing)

Runtime/Messaging/RpcAttributes.cs

@@ -21,12 +21,36 @@ namespace Unity.Netcode
     /// <summary>
     /// <para>Represents the common base class for Rpc attributes.</para>
     /// </summary>
-    public abstract class RpcAttribute : Attribute
+    [AttributeUsage(AttributeTargets.Method)]
+    public class RpcAttribute : Attribute
     {
+        // Must match the set of parameters below
+        public struct RpcAttributeParams
+        {
+            public RpcDelivery Delivery;
+            public bool RequireOwnership;
+            public bool DeferLocal;
+            public bool AllowTargetOverride;
+        }
+
+        // Must match the fields in RemoteAttributeParams
         /// <summary>
         /// Type of RPC delivery method
         /// </summary>
         public RpcDelivery Delivery = RpcDelivery.Reliable;
+        public bool RequireOwnership;
+        public bool DeferLocal;
+        public bool AllowTargetOverride;
+
+        public RpcAttribute(SendTo target)
+        {
+        }
+
+        // To get around an issue with the release validator, RuntimeAccessModifiersILPP will make this 'public'
+        private RpcAttribute()
+        {
+
+        }
     }
 
     /// <summary>
@@ -36,10 +60,12 @@ namespace Unity.Netcode
     [AttributeUsage(AttributeTargets.Method)]
     public class ServerRpcAttribute : RpcAttribute
     {
-        /// <summary>
-        /// Whether or not the ServerRpc should only be run if executed by the owner of the object
-        /// </summary>
-        public bool RequireOwnership = true;
+        public new bool RequireOwnership;
+
+        public ServerRpcAttribute() : base(SendTo.Server)
+        {
+
+        }
     }
 
     /// <summary>
@@ -47,5 +73,11 @@ namespace Unity.Netcode
     /// <para>A ClientRpc marked method will be fired by the server but executed on clients.</para>
     /// </summary>
     [AttributeUsage(AttributeTargets.Method)]
-    public class ClientRpcAttribute : RpcAttribute { }
+    public class ClientRpcAttribute : RpcAttribute
+    {
+        public ClientRpcAttribute() : base(SendTo.NotServer)
+        {
+
+        }
+    }
 }

Runtime/Messaging/RpcParams.cs

@@ -3,6 +3,60 @@ using Unity.Collections;
 
 namespace Unity.Netcode
 {
+    public enum LocalDeferMode
+    {
+        Default,
+        Defer,
+        SendImmediate
+    }
+    /// <summary>
+    /// Generic RPC
+    /// </summary>
+    public struct RpcSendParams
+    {
+        public BaseRpcTarget Target;
+
+        public LocalDeferMode LocalDeferMode;
+
+        public static implicit operator RpcSendParams(BaseRpcTarget target) => new RpcSendParams { Target = target };
+        public static implicit operator RpcSendParams(LocalDeferMode deferMode) => new RpcSendParams { LocalDeferMode = deferMode };
+    }
+
+    /// <summary>
+    /// The receive parameters for server-side remote procedure calls
+    /// </summary>
+    public struct RpcReceiveParams
+    {
+        /// <summary>
+        /// Server-Side RPC
+        /// The client identifier of the sender
+        /// </summary>
+        public ulong SenderClientId;
+    }
+
+    /// <summary>
+    /// Server-Side RPC
+    /// Can be used with any sever-side remote procedure call
+    /// Note: typically this is use primarily for the <see cref="ServerRpcReceiveParams"/>
+    /// </summary>
+    public struct RpcParams
+    {
+        /// <summary>
+        /// The server RPC send parameters (currently a place holder)
+        /// </summary>
+        public RpcSendParams Send;
+
+        /// <summary>
+        /// The client RPC receive parameters provides you with the sender's identifier
+        /// </summary>
+        public RpcReceiveParams Receive;
+
+        public static implicit operator RpcParams(RpcSendParams send) => new RpcParams { Send = send };
+        public static implicit operator RpcParams(BaseRpcTarget target) => new RpcParams { Send = new RpcSendParams { Target = target } };
+        public static implicit operator RpcParams(LocalDeferMode deferMode) => new RpcParams { Send = new RpcSendParams { LocalDeferMode = deferMode } };
+        public static implicit operator RpcParams(RpcReceiveParams receive) => new RpcParams { Receive = receive };
+    }
+
     /// <summary>
     /// Server-Side RPC
     /// Place holder.  <see cref="ServerRpcParams"/>
@@ -99,6 +153,7 @@ namespace Unity.Netcode
     internal struct __RpcParams
 #pragma warning restore IDE1006 // restore naming rule violation check
     {
+        public RpcParams Ext;
         public ServerRpcParams Server;
         public ClientRpcParams Client;
     }

Runtime/Messaging/RpcTargets.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: b02186acd1144e20acbd0dcb69b14938
+timeCreated: 1697824888

Runtime/Messaging/RpcTargets/AuthorityRpcTarget.cs

@@ -0,0 +1,75 @@
+namespace Unity.Netcode
+{
+    internal class AuthorityRpcTarget : ServerRpcTarget
+    {
+        private ProxyRpcTarget m_AuthorityTarget;
+        private DirectSendRpcTarget m_DirectSendTarget;
+
+        public override void Dispose()
+        {
+            if (m_AuthorityTarget != null)
+            {
+                m_AuthorityTarget.Dispose();
+                m_AuthorityTarget = null;
+            }
+
+            if (m_DirectSendTarget != null)
+            {
+                m_DirectSendTarget.Dispose();
+                m_DirectSendTarget = null;
+            }
+
+            base.Dispose();
+        }
+
+        internal override void Send(NetworkBehaviour behaviour, ref RpcMessage message, NetworkDelivery delivery, RpcParams rpcParams)
+        {
+            if (behaviour.NetworkManager.DistributedAuthorityMode)
+            {
+                // If invoked locally, then send locally
+                if (behaviour.HasAuthority)
+                {
+                    if (m_UnderlyingTarget == null)
+                    {
+                        m_UnderlyingTarget = new LocalSendRpcTarget(m_NetworkManager);
+                    }
+                    m_UnderlyingTarget.Send(behaviour, ref message, delivery, rpcParams);
+                }
+                else if (behaviour.NetworkManager.DAHost)
+                {
+                    if (m_DirectSendTarget == null)
+                    {
+                        m_DirectSendTarget = new DirectSendRpcTarget(behaviour.OwnerClientId, m_NetworkManager);
+                    }
+                    else
+                    {
+                        m_DirectSendTarget.ClientId = behaviour.OwnerClientId;
+                    }
+                    m_DirectSendTarget.Send(behaviour, ref message, delivery, rpcParams);
+                }
+                else // Otherwise (for now), we always proxy the RPC messages to the owner
+                {
+                    if (m_AuthorityTarget == null)
+                    {
+                        m_AuthorityTarget = new ProxyRpcTarget(behaviour.OwnerClientId, m_NetworkManager);
+                    }
+                    else
+                    {
+                        // Since the owner can change, for now we will just clear and set the owner each time
+                        m_AuthorityTarget.SetClientId(behaviour.OwnerClientId);
+                    }
+                    m_AuthorityTarget.Send(behaviour, ref message, delivery, rpcParams);
+                }
+            }
+            else
+            {
+                // If we are not in distributed authority mode, then we invoke the normal ServerRpc code.
+                base.Send(behaviour, ref message, delivery, rpcParams);
+            }
+        }
+
+        internal AuthorityRpcTarget(NetworkManager manager) : base(manager)
+        {
+        }
+    }
+}

Runtime/Messaging/RpcTargets/AuthorityRpcTarget.cs.meta

@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 6b8f28b7a617fd34faee91e5f88e89ac
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Runtime/Messaging/RpcTargets/BaseRpcTarget.cs

@@ -0,0 +1,57 @@
+using System;
+
+namespace Unity.Netcode
+{
+    public abstract class BaseRpcTarget : IDisposable
+    {
+        protected NetworkManager m_NetworkManager;
+        private bool m_Locked;
+
+        internal void Lock()
+        {
+            m_Locked = true;
+        }
+
+        internal void Unlock()
+        {
+            m_Locked = false;
+        }
+
+        internal BaseRpcTarget(NetworkManager manager)
+        {
+            m_NetworkManager = manager;
+        }
+
+        protected void CheckLockBeforeDispose()
+        {
+            if (m_Locked)
+            {
+                throw new Exception($"RPC targets obtained through {nameof(RpcTargetUse)}.{RpcTargetUse.Temp} may not be disposed.");
+            }
+        }
+
+        public abstract void Dispose();
+
+        internal abstract void Send(NetworkBehaviour behaviour, ref RpcMessage message, NetworkDelivery delivery, RpcParams rpcParams);
+
+        private protected void SendMessageToClient(NetworkBehaviour behaviour, ulong clientId, ref RpcMessage message, NetworkDelivery delivery)
+        {
+#if DEVELOPMENT_BUILD || UNITY_EDITOR
+            var size =
+#endif
+                behaviour.NetworkManager.MessageManager.SendMessage(ref message, delivery, clientId);
+
+#if DEVELOPMENT_BUILD || UNITY_EDITOR
+            if (NetworkBehaviour.__rpc_name_table[behaviour.GetType()].TryGetValue(message.Metadata.NetworkRpcMethodId, out var rpcMethodName))
+            {
+                behaviour.NetworkManager.NetworkMetrics.TrackRpcSent(
+                    clientId,
+                    behaviour.NetworkObject,
+                    rpcMethodName,
+                    behaviour.__getTypeName(),
+                    size);
+            }
+#endif
+        }
+    }
+}

Runtime/Messaging/RpcTargets/BaseRpcTarget.cs.meta

@@ -0,0 +1,11 @@
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+guid: 07c2620262e24eb5a426b521c09b3091
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Runtime/Messaging/RpcTargets/ClientsAndHostRpcTarget.cs

@@ -0,0 +1,37 @@
+namespace Unity.Netcode
+{
+    internal class ClientsAndHostRpcTarget : BaseRpcTarget
+    {
+        private BaseRpcTarget m_UnderlyingTarget;
+
+        public override void Dispose()
+        {
+            m_UnderlyingTarget = null;
+        }
+
+        internal override void Send(NetworkBehaviour behaviour, ref RpcMessage message, NetworkDelivery delivery, RpcParams rpcParams)
+        {
+            if (m_UnderlyingTarget == null)
+            {
+                // NotServer treats a host as being a server and will not send to it
+                // ClientsAndHost sends to everyone who runs any client logic
+                // So if the server is a host, this target includes it (as hosts run client logic)
+                // If the server is not a host, this target leaves it out, ergo the selection of NotServer.
+                if (behaviour.NetworkManager.ServerIsHost)
+                {
+                    m_UnderlyingTarget = behaviour.RpcTarget.Everyone;
+                }
+                else
+                {
+                    m_UnderlyingTarget = behaviour.RpcTarget.NotServer;
+                }
+            }
+
+            m_UnderlyingTarget.Send(behaviour, ref message, delivery, rpcParams);
+        }
+
+        internal ClientsAndHostRpcTarget(NetworkManager manager) : base(manager)
+        {
+        }
+    }
+}

Runtime/Messaging/RpcTargets/ClientsAndHostRpcTarget.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: c9f883d678ec4715b160dd9497d5f42d
+timeCreated: 1699481382

Runtime/Messaging/RpcTargets/DirectSendRpcTarget.cs

@@ -0,0 +1,34 @@
+namespace Unity.Netcode
+{
+    internal class DirectSendRpcTarget : BaseRpcTarget, IIndividualRpcTarget
+    {
+        public BaseRpcTarget Target => this;
+
+        internal ulong ClientId;
+
+        public override void Dispose()
+        {
+            CheckLockBeforeDispose();
+        }
+
+        internal override void Send(NetworkBehaviour behaviour, ref RpcMessage message, NetworkDelivery delivery, RpcParams rpcParams)
+        {
+            SendMessageToClient(behaviour, ClientId, ref message, delivery);
+        }
+
+        public void SetClientId(ulong clientId)
+        {
+            ClientId = clientId;
+        }
+
+        internal DirectSendRpcTarget(NetworkManager manager) : base(manager)
+        {
+
+        }
+
+        internal DirectSendRpcTarget(ulong clientId, NetworkManager manager) : base(manager)
+        {
+            ClientId = clientId;
+        }
+    }
+}

Runtime/Messaging/RpcTargets/DirectSendRpcTarget.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: 077544cfd0b94cfc8a2a55d3828b74bb
+timeCreated: 1697824873

Runtime/Messaging/RpcTargets/EveryoneRpcTarget.cs

@@ -0,0 +1,26 @@
+namespace Unity.Netcode
+{
+    internal class EveryoneRpcTarget : BaseRpcTarget
+    {
+        private NotServerRpcTarget m_NotServerRpcTarget;
+        private ServerRpcTarget m_ServerRpcTarget;
+
+        public override void Dispose()
+        {
+            m_NotServerRpcTarget.Dispose();
+            m_ServerRpcTarget.Dispose();
+        }
+
+        internal override void Send(NetworkBehaviour behaviour, ref RpcMessage message, NetworkDelivery delivery, RpcParams rpcParams)
+        {
+            m_NotServerRpcTarget.Send(behaviour, ref message, delivery, rpcParams);
+            m_ServerRpcTarget.Send(behaviour, ref message, delivery, rpcParams);
+        }
+
+        internal EveryoneRpcTarget(NetworkManager manager) : base(manager)
+        {
+            m_NotServerRpcTarget = new NotServerRpcTarget(manager);
+            m_ServerRpcTarget = new ServerRpcTarget(manager);
+        }
+    }
+}

Runtime/Messaging/RpcTargets/EveryoneRpcTarget.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: 675d4a5c79fc47078092ac15d255745d
+timeCreated: 1697824941

Runtime/Messaging/RpcTargets/IGroupRpcTarget.cs

@@ -0,0 +1,9 @@
+namespace Unity.Netcode
+{
+    internal interface IGroupRpcTarget
+    {
+        void Add(ulong clientId);
+        void Clear();
+        BaseRpcTarget Target { get; }
+    }
+}

Runtime/Messaging/RpcTargets/IGroupRpcTarget.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: beb19a6bb1334252a89b21c8490f7cbe
+timeCreated: 1697825109

Runtime/Messaging/RpcTargets/IIndividualRpcTarget.cs

@@ -0,0 +1,8 @@
+namespace Unity.Netcode
+{
+    internal interface IIndividualRpcTarget
+    {
+        void SetClientId(ulong clientId);
+        BaseRpcTarget Target { get; }
+    }
+}

Runtime/Messaging/RpcTargets/IIndividualRpcTarget.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: c658d9641f564d9890bef4f558f1cea6
+timeCreated: 1697825115

Runtime/Messaging/RpcTargets/LocalSendRpcTarget.cs

@@ -0,0 +1,67 @@
+using Unity.Collections;
+using Unity.Collections.LowLevel.Unsafe;
+
+namespace Unity.Netcode
+{
+    internal class LocalSendRpcTarget : BaseRpcTarget
+    {
+        public override void Dispose()
+        {
+
+        }
+
+        internal override void Send(NetworkBehaviour behaviour, ref RpcMessage message, NetworkDelivery delivery, RpcParams rpcParams)
+        {
+            var networkManager = behaviour.NetworkManager;
+            var context = new NetworkContext
+            {
+                SenderId = m_NetworkManager.LocalClientId,
+                Timestamp = networkManager.RealTimeProvider.RealTimeSinceStartup,
+                SystemOwner = networkManager,
+                // header information isn't valid since it's not a real message.
+                // RpcMessage doesn't access this stuff so it's just left empty.
+                Header = new NetworkMessageHeader(),
+                SerializedHeaderSize = 0,
+                MessageSize = 0
+            };
+            int length;
+            if (rpcParams.Send.LocalDeferMode == LocalDeferMode.Defer)
+            {
+                using var serializedWriter = new FastBufferWriter(message.WriteBuffer.Length + UnsafeUtility.SizeOf<RpcMetadata>(), Allocator.Temp, int.MaxValue);
+                message.Serialize(serializedWriter, message.Version);
+                using var reader = new FastBufferReader(serializedWriter, Allocator.None);
+                context.Header = new NetworkMessageHeader
+                {
+                    MessageSize = (uint)reader.Length,
+                    MessageType = m_NetworkManager.MessageManager.GetMessageType(typeof(RpcMessage))
+                };
+
+                networkManager.DeferredMessageManager.DeferMessage(IDeferredNetworkMessageManager.TriggerType.OnNextFrame, 0, reader, ref context);
+                length = reader.Length;
+            }
+            else
+            {
+                using var tempBuffer = new FastBufferReader(message.WriteBuffer, Allocator.None);
+                message.ReadBuffer = tempBuffer;
+                message.Handle(ref context);
+                length = tempBuffer.Length;
+            }
+#if DEVELOPMENT_BUILD || UNITY_EDITOR
+            if (NetworkBehaviour.__rpc_name_table[behaviour.GetType()].TryGetValue(message.Metadata.NetworkRpcMethodId, out var rpcMethodName))
+            {
+                networkManager.NetworkMetrics.TrackRpcSent(
+                    networkManager.LocalClientId,
+                    behaviour.NetworkObject,
+                    rpcMethodName,
+                    behaviour.__getTypeName(),
+                    length);
+            }
+#endif
+        }
+
+        internal LocalSendRpcTarget(NetworkManager manager) : base(manager)
+        {
+
+        }
+    }
+}

Runtime/Messaging/RpcTargets/LocalSendRpcTarget.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: c3b290cdc20d4d2293652ec79652962a
+timeCreated: 1697824985

Runtime/Messaging/RpcTargets/NotAuthorityRpcTarget.cs

@@ -0,0 +1,65 @@
+namespace Unity.Netcode
+{
+    internal class NotAuthorityRpcTarget : NotServerRpcTarget
+    {
+        internal override void Send(NetworkBehaviour behaviour, ref RpcMessage message, NetworkDelivery delivery, RpcParams rpcParams)
+        {
+            var networkObject = behaviour.NetworkObject;
+            if (m_NetworkManager.DistributedAuthorityMode)
+            {
+                if (m_GroupSendTarget == null)
+                {
+                    // When mocking the CMB service, we are running a server so create a non-proxy target group
+                    if (m_NetworkManager.DAHost)
+                    {
+                        m_GroupSendTarget = new RpcTargetGroup(m_NetworkManager);
+                    }
+                    else // Otherwise (for now), we always proxy the RPC messages
+                    {
+                        m_GroupSendTarget = new ProxyRpcTargetGroup(m_NetworkManager);
+                    }
+                }
+                m_GroupSendTarget.Clear();
+
+                if (behaviour.HasAuthority)
+                {
+                    foreach (var clientId in networkObject.Observers)
+                    {
+                        if (clientId == behaviour.OwnerClientId)
+                        {
+                            continue;
+                        }
+                        m_GroupSendTarget.Add(clientId);
+                    }
+                }
+                else
+                {
+                    foreach (var clientId in m_NetworkManager.ConnectedClientsIds)
+                    {
+                        if (clientId == behaviour.OwnerClientId || !networkObject.Observers.Contains(clientId))
+                        {
+                            continue;
+                        }
+
+                        if (clientId == m_NetworkManager.LocalClientId)
+                        {
+                            m_LocalSendRpcTarget.Send(behaviour, ref message, delivery, rpcParams);
+                            continue;
+                        }
+                        m_GroupSendTarget.Add(clientId);
+                    }
+                }
+
+                m_GroupSendTarget.Target.Send(behaviour, ref message, delivery, rpcParams);
+            }
+            else
+            {
+                base.Send(behaviour, ref message, delivery, rpcParams);
+            }
+        }
+
+        internal NotAuthorityRpcTarget(NetworkManager manager) : base(manager)
+        {
+        }
+    }
+}

Runtime/Messaging/RpcTargets/NotAuthorityRpcTarget.cs.meta

@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 4968ce7e70c277d4a892c1ed209ce4d6
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Runtime/Messaging/RpcTargets/NotMeRpcTarget.cs

@@ -0,0 +1,74 @@
+namespace Unity.Netcode
+{
+    internal class NotMeRpcTarget : BaseRpcTarget
+    {
+        private IGroupRpcTarget m_GroupSendTarget;
+        private ServerRpcTarget m_ServerRpcTarget;
+
+        public override void Dispose()
+        {
+            m_ServerRpcTarget.Dispose();
+            if (m_GroupSendTarget != null)
+            {
+                m_GroupSendTarget.Target.Dispose();
+                m_GroupSendTarget = null;
+            }
+        }
+
+        internal override void Send(NetworkBehaviour behaviour, ref RpcMessage message, NetworkDelivery delivery, RpcParams rpcParams)
+        {
+            if (m_GroupSendTarget == null)
+            {
+                if (behaviour.IsServer)
+                {
+                    m_GroupSendTarget = new RpcTargetGroup(m_NetworkManager);
+                }
+                else
+                {
+                    m_GroupSendTarget = new ProxyRpcTargetGroup(m_NetworkManager);
+                }
+            }
+
+            m_GroupSendTarget.Clear();
+            if (behaviour.IsServer)
+            {
+                foreach (var clientId in behaviour.NetworkObject.Observers)
+                {
+                    if (clientId == behaviour.NetworkManager.LocalClientId)
+                    {
+                        continue;
+                    }
+                    m_GroupSendTarget.Add(clientId);
+                }
+            }
+            else
+            {
+                foreach (var clientId in m_NetworkManager.ConnectedClientsIds)
+                {
+                    if (clientId == behaviour.NetworkManager.LocalClientId)
+                    {
+                        continue;
+                    }
+                    // In distributed authority mode, we send to target id 0 (which would be a DAHost) via the group
+                    if (clientId == NetworkManager.ServerClientId && !m_NetworkManager.DistributedAuthorityMode)
+                    {
+                        continue;
+                    }
+                    m_GroupSendTarget.Add(clientId);
+                }
+            }
+            m_GroupSendTarget.Target.Send(behaviour, ref message, delivery, rpcParams);
+
+            // In distributed authority mode, we don't use ServerRpc
+            if (!behaviour.IsServer && !m_NetworkManager.DistributedAuthorityMode)
+            {
+                m_ServerRpcTarget.Send(behaviour, ref message, delivery, rpcParams);
+            }
+        }
+
+        internal NotMeRpcTarget(NetworkManager manager) : base(manager)
+        {
+            m_ServerRpcTarget = new ServerRpcTarget(manager);
+        }
+    }
+}

Runtime/Messaging/RpcTargets/NotMeRpcTarget.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: 99cd5e8be7bd454bab700ee08b8dad7b
+timeCreated: 1697824966

Runtime/Messaging/RpcTargets/NotOwnerRpcTarget.cs

@@ -0,0 +1,91 @@
+namespace Unity.Netcode
+{
+    internal class NotOwnerRpcTarget : BaseRpcTarget
+    {
+        private IGroupRpcTarget m_GroupSendTarget;
+        private ServerRpcTarget m_ServerRpcTarget;
+        private LocalSendRpcTarget m_LocalSendRpcTarget;
+
+        public override void Dispose()
+        {
+            m_ServerRpcTarget.Dispose();
+            m_LocalSendRpcTarget.Dispose();
+            if (m_GroupSendTarget != null)
+            {
+                m_GroupSendTarget.Target.Dispose();
+                m_GroupSendTarget = null;
+            }
+        }
+
+        internal override void Send(NetworkBehaviour behaviour, ref RpcMessage message, NetworkDelivery delivery, RpcParams rpcParams)
+        {
+            if (m_GroupSendTarget == null)
+            {
+                if (behaviour.IsServer)
+                {
+                    m_GroupSendTarget = new RpcTargetGroup(m_NetworkManager);
+                }
+                else
+                {
+                    m_GroupSendTarget = new ProxyRpcTargetGroup(m_NetworkManager);
+                }
+            }
+            m_GroupSendTarget.Clear();
+
+            if (behaviour.IsServer)
+            {
+                foreach (var clientId in behaviour.NetworkObject.Observers)
+                {
+                    if (clientId == behaviour.OwnerClientId)
+                    {
+                        continue;
+                    }
+                    if (clientId == NetworkManager.ServerClientId)
+                    {
+                        continue;
+                    }
+                    if (clientId == behaviour.NetworkManager.LocalClientId)
+                    {
+                        m_LocalSendRpcTarget.Send(behaviour, ref message, delivery, rpcParams);
+                        continue;
+                    }
+
+                    m_GroupSendTarget.Add(clientId);
+                }
+            }
+            else
+            {
+                foreach (var clientId in m_NetworkManager.ConnectedClientsIds)
+                {
+                    if (clientId == behaviour.OwnerClientId)
+                    {
+                        continue;
+                    }
+                    if (clientId == NetworkManager.ServerClientId)
+                    {
+                        continue;
+                    }
+                    if (clientId == behaviour.NetworkManager.LocalClientId)
+                    {
+                        m_LocalSendRpcTarget.Send(behaviour, ref message, delivery, rpcParams);
+                        continue;
+                    }
+
+                    m_GroupSendTarget.Add(clientId);
+                }
+            }
+
+            m_GroupSendTarget.Target.Send(behaviour, ref message, delivery, rpcParams);
+            if (behaviour.OwnerClientId != NetworkManager.ServerClientId)
+            {
+                m_ServerRpcTarget.Send(behaviour, ref message, delivery, rpcParams);
+            }
+        }
+
+        internal NotOwnerRpcTarget(NetworkManager manager) : base(manager)
+        {
+            m_ServerRpcTarget = new ServerRpcTarget(manager);
+            m_LocalSendRpcTarget = new LocalSendRpcTarget(manager);
+        }
+    }
+}

Runtime/Messaging/RpcTargets/NotOwnerRpcTarget.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: d7bc66c5253b44d09ad978ea9e51c96f
+timeCreated: 1698789420

Runtime/Messaging/RpcTargets/NotServerRpcTarget.cs

@@ -0,0 +1,72 @@
+namespace Unity.Netcode
+{
+    internal class NotServerRpcTarget : BaseRpcTarget
+    {
+        protected IGroupRpcTarget m_GroupSendTarget;
+        protected LocalSendRpcTarget m_LocalSendRpcTarget;
+
+        public override void Dispose()
+        {
+            m_LocalSendRpcTarget.Dispose();
+            if (m_GroupSendTarget != null)
+            {
+                m_GroupSendTarget.Target.Dispose();
+                m_GroupSendTarget = null;
+            }
+        }
+
+        internal override void Send(NetworkBehaviour behaviour, ref RpcMessage message, NetworkDelivery delivery, RpcParams rpcParams)
+        {
+            if (m_GroupSendTarget == null)
+            {
+                if (behaviour.IsServer)
+                {
+                    m_GroupSendTarget = new RpcTargetGroup(m_NetworkManager);
+                }
+                else
+                {
+                    m_GroupSendTarget = new ProxyRpcTargetGroup(m_NetworkManager);
+                }
+            }
+            m_GroupSendTarget.Clear();
+
+            if (behaviour.IsServer)
+            {
+                foreach (var clientId in behaviour.NetworkObject.Observers)
+                {
+                    if (clientId == NetworkManager.ServerClientId)
+                    {
+                        continue;
+                    }
+
+                    m_GroupSendTarget.Add(clientId);
+                }
+            }
+            else
+            {
+                foreach (var clientId in m_NetworkManager.ConnectedClientsIds)
+                {
+                    if (clientId == NetworkManager.ServerClientId)
+                    {
+                        continue;
+                    }
+
+                    if (clientId == behaviour.NetworkManager.LocalClientId)
+                    {
+                        m_LocalSendRpcTarget.Send(behaviour, ref message, delivery, rpcParams);
+                        continue;
+                    }
+
+                    m_GroupSendTarget.Add(clientId);
+                }
+            }
+
+            m_GroupSendTarget.Target.Send(behaviour, ref message, delivery, rpcParams);
+        }
+
+        internal NotServerRpcTarget(NetworkManager manager) : base(manager)
+        {
+            m_LocalSendRpcTarget = new LocalSendRpcTarget(manager);
+        }
+    }
+}

Runtime/Messaging/RpcTargets/NotServerRpcTarget.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: c63787afe52f45ffbd5d801f78e7c0d6
+timeCreated: 1697824954

Runtime/Messaging/RpcTargets/OwnerRpcTarget.cs

@@ -0,0 +1,54 @@
+namespace Unity.Netcode
+{
+    internal class OwnerRpcTarget : BaseRpcTarget
+    {
+        private IIndividualRpcTarget m_UnderlyingTarget;
+        private LocalSendRpcTarget m_LocalRpcTarget;
+        private ServerRpcTarget m_ServerRpcTarget;
+
+        public override void Dispose()
+        {
+            m_LocalRpcTarget.Dispose();
+            if (m_UnderlyingTarget != null)
+            {
+                m_UnderlyingTarget.Target.Dispose();
+                m_UnderlyingTarget = null;
+            }
+        }
+
+        internal override void Send(NetworkBehaviour behaviour, ref RpcMessage message, NetworkDelivery delivery, RpcParams rpcParams)
+        {
+            if (behaviour.OwnerClientId == behaviour.NetworkManager.LocalClientId)
+            {
+                m_LocalRpcTarget.Send(behaviour, ref message, delivery, rpcParams);
+                return;
+            }
+
+            if (behaviour.OwnerClientId == NetworkManager.ServerClientId)
+            {
+                m_ServerRpcTarget.Send(behaviour, ref message, delivery, rpcParams);
+                return;
+            }
+
+            if (m_UnderlyingTarget == null)
+            {
+                if (behaviour.NetworkManager.IsServer)
+                {
+                    m_UnderlyingTarget = new DirectSendRpcTarget(m_NetworkManager);
+                }
+                else
+                {
+                    m_UnderlyingTarget = new ProxyRpcTarget(behaviour.OwnerClientId, m_NetworkManager);
+                }
+            }
+            m_UnderlyingTarget.SetClientId(behaviour.OwnerClientId);
+            m_UnderlyingTarget.Target.Send(behaviour, ref message, delivery, rpcParams);
+        }
+
+        internal OwnerRpcTarget(NetworkManager manager) : base(manager)
+        {
+            m_LocalRpcTarget = new LocalSendRpcTarget(manager);
+            m_ServerRpcTarget = new ServerRpcTarget(manager);
+        }
+    }
+}

Runtime/Messaging/RpcTargets/OwnerRpcTarget.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: 23c4d52455fc419aaf03094617894257
+timeCreated: 1697824972

Runtime/Messaging/RpcTargets/ProxyRpcTarget.cs

@@ -0,0 +1,16 @@
+namespace Unity.Netcode
+{
+    internal class ProxyRpcTarget : ProxyRpcTargetGroup, IIndividualRpcTarget
+    {
+        internal ProxyRpcTarget(ulong clientId, NetworkManager manager) : base(manager)
+        {
+            Add(clientId);
+        }
+
+        public void SetClientId(ulong clientId)
+        {
+            Clear();
+            Add(clientId);
+        }
+    }
+}

Runtime/Messaging/RpcTargets/ProxyRpcTarget.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: 86002805bb9e422e8b71581d1325357f
+timeCreated: 1697825007

Runtime/Messaging/RpcTargets/ProxyRpcTargetGroup.cs

@@ -0,0 +1,100 @@
+using System;
+using System.Collections.Generic;
+using Unity.Collections;
+
+namespace Unity.Netcode
+{
+    internal class ProxyRpcTargetGroup : BaseRpcTarget, IDisposable, IGroupRpcTarget
+    {
+        public BaseRpcTarget Target => this;
+
+        private ServerRpcTarget m_ServerRpcTarget;
+        private LocalSendRpcTarget m_LocalSendRpcTarget;
+
+        private bool m_Disposed;
+        public NativeList<ulong> TargetClientIds;
+        internal HashSet<ulong> Ids = new HashSet<ulong>();
+
+        internal override void Send(NetworkBehaviour behaviour, ref RpcMessage message, NetworkDelivery delivery, RpcParams rpcParams)
+        {
+            var proxyMessage = new ProxyMessage { Delivery = delivery, TargetClientIds = TargetClientIds.AsArray(), WrappedMessage = message };
+#if DEVELOPMENT_BUILD || UNITY_EDITOR
+            var size =
+#endif
+                behaviour.NetworkManager.MessageManager.SendMessage(ref proxyMessage, delivery, NetworkManager.ServerClientId);
+
+#if DEVELOPMENT_BUILD || UNITY_EDITOR
+            if (NetworkBehaviour.__rpc_name_table[behaviour.GetType()].TryGetValue(message.Metadata.NetworkRpcMethodId, out var rpcMethodName))
+            {
+                foreach (var clientId in TargetClientIds)
+                {
+                    behaviour.NetworkManager.NetworkMetrics.TrackRpcSent(
+                        clientId,
+                        behaviour.NetworkObject,
+                        rpcMethodName,
+                        behaviour.__getTypeName(),
+                        size);
+                }
+            }
+#endif
+            if (Ids.Contains(NetworkManager.ServerClientId))
+            {
+                m_ServerRpcTarget.Send(behaviour, ref message, delivery, rpcParams);
+            }
+            if (Ids.Contains(m_NetworkManager.LocalClientId))
+            {
+                m_LocalSendRpcTarget.Send(behaviour, ref message, delivery, rpcParams);
+            }
+        }
+
+        internal ProxyRpcTargetGroup(NetworkManager manager) : base(manager)
+        {
+            TargetClientIds = new NativeList<ulong>(Allocator.Persistent);
+            m_ServerRpcTarget = new ServerRpcTarget(manager);
+            m_LocalSendRpcTarget = new LocalSendRpcTarget(manager);
+        }
+
+        public override void Dispose()
+        {
+            CheckLockBeforeDispose();
+            if (!m_Disposed)
+            {
+                TargetClientIds.Dispose();
+                m_Disposed = true;
+                m_ServerRpcTarget.Dispose();
+                m_LocalSendRpcTarget.Dispose();
+            }
+        }
+
+        public void Add(ulong clientId)
+        {
+            if (!Ids.Contains(clientId))
+            {
+                Ids.Add(clientId);
+                if (clientId != NetworkManager.ServerClientId && clientId != m_NetworkManager.LocalClientId)
+                {
+                    TargetClientIds.Add(clientId);
+                }
+            }
+        }
+
+        public void Remove(ulong clientId)
+        {
+            Ids.Remove(clientId);
+            for (var i = 0; i < TargetClientIds.Length; ++i)
+            {
+                if (TargetClientIds[i] == clientId)
+                {
+                    TargetClientIds.RemoveAt(i);
+                    break;
+                }
+            }
+        }
+
+        public void Clear()
+        {
+            Ids.Clear();
+            TargetClientIds.Clear();
+        }
+    }
+}

Runtime/Messaging/RpcTargets/ProxyRpcTargetGroup.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: 5728dbab532e46a88127510b4ec75af9
+timeCreated: 1697825000

Runtime/Messaging/RpcTargets/RpcTarget.cs

@@ -0,0 +1,591 @@
+using System.Collections.Generic;
+using Unity.Collections;
+
+namespace Unity.Netcode
+{
+    /// <summary>
+    /// Configuration for the default method by which an RPC is communicated across the network
+    /// </summary>
+    public enum SendTo
+    {
+        /// <summary>
+        /// Send to the NetworkObject's current owner.
+        /// Will execute locally if the local process is the owner.
+        /// </summary>
+        Owner,
+        /// <summary>
+        /// Send to everyone but the current owner, filtered to the current observer list.
+        /// Will execute locally if the local process is not the owner.
+        /// </summary>
+        NotOwner,
+        /// <summary>
+        /// Send to the server, regardless of ownership.
+        /// Will execute locally if invoked on the server.
+        /// </summary>
+        Server,
+        /// <summary>
+        /// Send to everyone but the server, filtered to the current observer list.
+        /// Will NOT send to a server running in host mode - it is still treated as a server.
+        /// If you want to send to servers when they are host, but not when they are dedicated server, use
+        /// <see cref="ClientsAndHost"/>.
+        /// <br />
+        /// <br />
+        /// Will execute locally if invoked on a client.
+        /// Will NOT execute locally if invoked on a server running in host mode.
+        /// </summary>
+        NotServer,
+        /// <summary>
+        /// Execute this RPC locally.
+        /// <br />
+        /// <br />
+        /// Normally this is no different from a standard function call.
+        /// <br />
+        /// <br />
+        /// Using the DeferLocal parameter of the attribute or the LocalDeferMode override in RpcSendParams,
+        /// this can allow an RPC to be processed on localhost with a one-frame delay as if it were sent over
+        /// the network.
+        /// </summary>
+        Me,
+        /// <summary>
+        /// Send this RPC to everyone but the local machine, filtered to the current observer list.
+        /// </summary>
+        NotMe,
+        /// <summary>
+        /// Send this RPC to everone, filtered to the current observer list.
+        /// Will execute locally.
+        /// </summary>
+        Everyone,
+        /// <summary>
+        /// Send this RPC to all clients, including the host, if a host exists.
+        /// If the server is running in host mode, this is the same as <see cref="Everyone" />.
+        /// If the server is running in dedicated server mode, this is the same as <see cref="NotServer" />.
+        /// </summary>
+        ClientsAndHost,
+        /// <summary>
+        /// Send this RPC to the authority.
+        /// In distributed authority mode, this will be the owner of the NetworkObject.
+        /// In normal client-server mode, this is basically the exact same thing as a server rpc.
+        /// </summary>
+        Authority,
+        /// <summary>
+        /// Send this RPC to all non-authority instances.
+        /// In distributed authority mode, this will be the non-owners of the NetworkObject.
+        /// In normal client-server mode, this is basically the exact same thing as a client rpc.
+        /// </summary>
+        NotAuthority,
+        /// <summary>
+        /// This RPC cannot be sent without passing in a target in RpcSendParams.
+        /// </summary>
+        SpecifiedInParams
+    }
+
+    public enum RpcTargetUse
+    {
+        Temp,
+        Persistent
+    }
+
+    /// <summary>
+    /// Implementations of the various <see cref="SendTo"/> options, as well as additional runtime-only options
+    /// <see cref="Single"/>,
+    /// <see cref="Group(NativeArray{ulong})"/>,
+    /// <see cref="Group(NativeList{ulong})"/>,
+    /// <see cref="Group(ulong[])"/>,
+    /// <see cref="Group{T}(T)"/>, <see cref="Not(ulong)"/>,
+    /// <see cref="Not(NativeArray{ulong})"/>,
+    /// <see cref="Not(NativeList{ulong})"/>,
+    /// <see cref="Not(ulong[])"/>, and
+    /// <see cref="Not{T}(T)"/>
+    /// </summary>
+    public class RpcTarget
+    {
+        private NetworkManager m_NetworkManager;
+        internal RpcTarget(NetworkManager manager)
+        {
+            m_NetworkManager = manager;
+
+            Everyone = new EveryoneRpcTarget(manager);
+            Owner = new OwnerRpcTarget(manager);
+            NotOwner = new NotOwnerRpcTarget(manager);
+            Server = new ServerRpcTarget(manager);
+            NotServer = new NotServerRpcTarget(manager);
+            NotMe = new NotMeRpcTarget(manager);
+            Me = new LocalSendRpcTarget(manager);
+            ClientsAndHost = new ClientsAndHostRpcTarget(manager);
+            Authority = new AuthorityRpcTarget(manager);
+            NotAuthority = new NotAuthorityRpcTarget(manager);
+            m_CachedProxyRpcTargetGroup = new ProxyRpcTargetGroup(manager);
+            m_CachedTargetGroup = new RpcTargetGroup(manager);
+            m_CachedDirectSendTarget = new DirectSendRpcTarget(manager);
+            m_CachedProxyRpcTarget = new ProxyRpcTarget(0, manager);
+
+            m_CachedProxyRpcTargetGroup.Lock();
+            m_CachedTargetGroup.Lock();
+            m_CachedDirectSendTarget.Lock();
+            m_CachedProxyRpcTarget.Lock();
+        }
+
+        public void Dispose()
+        {
+            Everyone.Dispose();
+            Owner.Dispose();
+            NotOwner.Dispose();
+            Server.Dispose();
+            NotServer.Dispose();
+            NotMe.Dispose();
+            Me.Dispose();
+            ClientsAndHost.Dispose();
+            Authority.Dispose();
+            NotAuthority.Dispose();
+            m_CachedProxyRpcTargetGroup.Unlock();
+            m_CachedTargetGroup.Unlock();
+            m_CachedDirectSendTarget.Unlock();
+            m_CachedProxyRpcTarget.Unlock();
+
+            m_CachedProxyRpcTargetGroup.Dispose();
+            m_CachedTargetGroup.Dispose();
+            m_CachedDirectSendTarget.Dispose();
+            m_CachedProxyRpcTarget.Dispose();
+        }
+
+        /// <summary>
+        /// Send to the NetworkObject's current owner.
+        /// Will execute locally if the local process is the owner.
+        /// </summary>
+        public BaseRpcTarget Owner;
+
+        /// <summary>
+        /// Send to everyone but the current owner, filtered to the current observer list.
+        /// Will execute locally if the local process is not the owner.
+        /// </summary>
+        public BaseRpcTarget NotOwner;
+
+        /// <summary>
+        /// Send to the server, regardless of ownership.
+        /// Will execute locally if invoked on the server.
+        /// </summary>
+        public BaseRpcTarget Server;
+
+        /// <summary>
+        /// Send to everyone but the server, filtered to the current observer list.
+        /// Will NOT send to a server running in host mode - it is still treated as a server.
+        /// If you want to send to servers when they are host, but not when they are dedicated server, use
+        /// <see cref="SendTo.ClientsAndHost"/>.
+        /// <br />
+        /// <br />
+        /// Will execute locally if invoked on a client.
+        /// Will NOT execute locally if invoked on a server running in host mode.
+        /// </summary>
+        public BaseRpcTarget NotServer;
+
+        /// <summary>
+        /// Execute this RPC locally.
+        /// <br />
+        /// <br />
+        /// Normally this is no different from a standard function call.
+        /// <br />
+        /// <br />
+        /// Using the DeferLocal parameter of the attribute or the LocalDeferMode override in RpcSendParams,
+        /// this can allow an RPC to be processed on localhost with a one-frame delay as if it were sent over
+        /// the network.
+        /// </summary>
+        public BaseRpcTarget Me;
+
+        /// <summary>
+        /// Send this RPC to everyone but the local machine, filtered to the current observer list.
+        /// </summary>
+        public BaseRpcTarget NotMe;
+
+        /// <summary>
+        /// Send this RPC to everone, filtered to the current observer list.
+        /// Will execute locally.
+        /// </summary>
+        public BaseRpcTarget Everyone;
+
+        /// <summary>
+        /// Send this RPC to all clients, including the host, if a host exists.
+        /// If the server is running in host mode, this is the same as <see cref="Everyone" />.
+        /// If the server is running in dedicated server mode, this is the same as <see cref="NotServer" />.
+        /// </summary>
+        public BaseRpcTarget ClientsAndHost;
+
+        /// <summary>
+        /// Send this RPC to the authority.
+        /// In distributed authority mode, this will be the owner of the NetworkObject.
+        /// In normal client-server mode, this is basically the exact same thing as a server rpc.
+        /// </summary>
+        public BaseRpcTarget Authority;
+
+        /// <summary>
+        /// Send this RPC to all non-authority instances.
+        /// In distributed authority mode, this will be the non-owners of the NetworkObject.
+        /// In normal client-server mode, this is basically the exact same thing as a client rpc.
+        /// </summary>
+        public BaseRpcTarget NotAuthority;
+
+        /// <summary>
+        /// Send to a specific single client ID.
+        /// </summary>
+        /// <param name="clientId"></param>
+        /// <param name="use"><see cref="RpcTargetUse.Temp"/> will return a cached target, which should not be stored as it will
+        /// be overwritten in future calls to Single(). Do not call Dispose() on Temp targets.<br /><br /><see cref="RpcTargetUse.Persistent"/> will
+        /// return a new target, which can be stored, but should not be done frequently because it results in a GC allocation. You must call Dispose() on Persistent targets when you are done with them.</param>
+        /// <returns></returns>
+        public BaseRpcTarget Single(ulong clientId, RpcTargetUse use)
+        {
+            if (clientId == m_NetworkManager.LocalClientId)
+            {
+                return Me;
+            }
+
+            if (m_NetworkManager.IsServer || clientId == NetworkManager.ServerClientId)
+            {
+                if (use == RpcTargetUse.Persistent)
+                {
+                    return new DirectSendRpcTarget(clientId, m_NetworkManager);
+                }
+                m_CachedDirectSendTarget.SetClientId(clientId);
+                return m_CachedDirectSendTarget;
+            }
+
+            if (use == RpcTargetUse.Persistent)
+            {
+                return new ProxyRpcTarget(clientId, m_NetworkManager);
+            }
+            m_CachedProxyRpcTarget.SetClientId(clientId);
+            return m_CachedProxyRpcTarget;
+        }
+
+        /// <summary>
+        /// Send to everyone EXCEPT a specific single client ID.
+        /// </summary>
+        /// <param name="excludedClientId"></param>
+        /// <param name="use"><see cref="RpcTargetUse.Temp"/> will return a cached target, which should not be stored as it will
+        /// be overwritten in future calls to Not() or Group(). Do not call Dispose() on Temp targets.<br /><br /><see cref="RpcTargetUse.Persistent"/> will
+        /// return a new target, which can be stored, but should not be done frequently because it results in a GC allocation. You must call Dispose() on Persistent targets when you are done with them.</param>
+        /// <returns></returns>
+        public BaseRpcTarget Not(ulong excludedClientId, RpcTargetUse use)
+        {
+            IGroupRpcTarget target;
+            if (m_NetworkManager.IsServer)
+            {
+                if (use == RpcTargetUse.Persistent)
+                {
+                    target = new RpcTargetGroup(m_NetworkManager);
+                }
+                else
+                {
+                    target = m_CachedTargetGroup;
+                }
+            }
+            else
+            {
+                if (use == RpcTargetUse.Persistent)
+                {
+                    target = new ProxyRpcTargetGroup(m_NetworkManager);
+                }
+                else
+                {
+                    target = m_CachedProxyRpcTargetGroup;
+                }
+            }
+            target.Clear();
+            foreach (var clientId in m_NetworkManager.ConnectedClientsIds)
+            {
+                if (clientId != excludedClientId)
+                {
+                    target.Add(clientId);
+                }
+            }
+
+            // If ServerIsHost, ConnectedClientIds already contains ServerClientId and this would duplicate it.
+            if (!m_NetworkManager.ServerIsHost && excludedClientId != NetworkManager.ServerClientId)
+            {
+                target.Add(NetworkManager.ServerClientId);
+            }
+
+            return target.Target;
+        }
+
+        /// <summary>
+        /// Sends to a group of client IDs.
+        /// NativeArrays can be trivially constructed using Allocator.Temp, making this an efficient
+        /// Group method if the group list is dynamically constructed.
+        /// </summary>
+        /// <param name="clientIds"></param>
+        /// <param name="use"><see cref="RpcTargetUse.Temp"/> will return a cached target, which should not be stored as it will
+        /// be overwritten in future calls to Not() or Group(). Do not call Dispose() on Temp targets.<br /><br /><see cref="RpcTargetUse.Persistent"/> will
+        /// return a new target, which can be stored, but should not be done frequently because it results in a GC allocation. You must call Dispose() on Persistent targets when you are done with them.</param>
+        /// <returns></returns>
+        public BaseRpcTarget Group(NativeArray<ulong> clientIds, RpcTargetUse use)
+        {
+            IGroupRpcTarget target;
+            if (m_NetworkManager.IsServer)
+            {
+                if (use == RpcTargetUse.Persistent)
+                {
+                    target = new RpcTargetGroup(m_NetworkManager);
+                }
+                else
+                {
+                    target = m_CachedTargetGroup;
+                }
+            }
+            else
+            {
+                if (use == RpcTargetUse.Persistent)
+                {
+                    target = new ProxyRpcTargetGroup(m_NetworkManager);
+                }
+                else
+                {
+                    target = m_CachedProxyRpcTargetGroup;
+                }
+            }
+            target.Clear();
+            foreach (var clientId in clientIds)
+            {
+                target.Add(clientId);
+            }
+
+            return target.Target;
+        }
+
+        /// <summary>
+        /// Sends to a group of client IDs.
+        /// NativeList can be trivially constructed using Allocator.Temp, making this an efficient
+        /// Group method if the group list is dynamically constructed.
+        /// </summary>
+        /// <param name="clientIds"></param>
+        /// <param name="use"><see cref="RpcTargetUse.Temp"/> will return a cached target, which should not be stored as it will
+        /// be overwritten in future calls to Not() or Group(). Do not call Dispose() on Temp targets.<br /><br /><see cref="RpcTargetUse.Persistent"/> will
+        /// return a new target, which can be stored, but should not be done frequently because it results in a GC allocation. You must call Dispose() on Persistent targets when you are done with them.</param>
+        /// <returns></returns>
+        public BaseRpcTarget Group(NativeList<ulong> clientIds, RpcTargetUse use)
+        {
+            var asArray = clientIds.AsArray();
+            return Group(asArray, use);
+        }
+
+        /// <summary>
+        /// Sends to a group of client IDs.
+        /// Constructing arrays requires garbage collected allocations. This override is only recommended
+        /// if you either have no strict performance requirements, or have the group of client IDs cached so
+        /// it is not created each time.
+        /// </summary>
+        /// <param name="clientIds"></param>
+        /// <param name="use"><see cref="RpcTargetUse.Temp"/> will return a cached target, which should not be stored as it will
+        /// be overwritten in future calls to Not() or Group(). Do not call Dispose() on Temp targets.<br /><br /><see cref="RpcTargetUse.Persistent"/> will
+        /// return a new target, which can be stored, but should not be done frequently because it results in a GC allocation. You must call Dispose() on Persistent targets when you are done with them.</param>
+        /// <returns></returns>
+        public BaseRpcTarget Group(ulong[] clientIds, RpcTargetUse use)
+        {
+            return Group(new NativeArray<ulong>(clientIds, Allocator.Temp), use);
+        }
+
+        /// <summary>
+        /// Sends to a group of client IDs.
+        /// This accepts any IEnumerable type, such as List&lt;ulong&gt;, but cannot be called without
+        /// a garbage collected allocation (even if the type itself is a struct type, due to boxing).
+        /// This override is only recommended if you either have no strict performance requirements,
+        /// or have the group of client IDs cached so it is not created each time.
+        /// </summary>
+        /// <param name="clientIds"></param>
+        /// <param name="use"><see cref="RpcTargetUse.Temp"/> will return a cached target, which should not be stored as it will
+        /// be overwritten in future calls to Not() or Group(). Do not call Dispose() on Temp targets.<br /><br /><see cref="RpcTargetUse.Persistent"/> will
+        /// return a new target, which can be stored, but should not be done frequently because it results in a GC allocation. You must call Dispose() on Persistent targets when you are done with them.</param>
+        /// <returns></returns>
+        public BaseRpcTarget Group<T>(T clientIds, RpcTargetUse use) where T : IEnumerable<ulong>
+        {
+            IGroupRpcTarget target;
+            if (m_NetworkManager.IsServer)
+            {
+                if (use == RpcTargetUse.Persistent)
+                {
+                    target = new RpcTargetGroup(m_NetworkManager);
+                }
+                else
+                {
+                    target = m_CachedTargetGroup;
+                }
+            }
+            else
+            {
+                if (use == RpcTargetUse.Persistent)
+                {
+                    target = new ProxyRpcTargetGroup(m_NetworkManager);
+                }
+                else
+                {
+                    target = m_CachedProxyRpcTargetGroup;
+                }
+            }
+            target.Clear();
+            foreach (var clientId in clientIds)
+            {
+                target.Add(clientId);
+            }
+
+            return target.Target;
+        }
+
+        /// <summary>
+        /// Sends to everyone EXCEPT a group of client IDs.
+        /// NativeArrays can be trivially constructed using Allocator.Temp, making this an efficient
+        /// Group method if the group list is dynamically constructed.
+        /// </summary>
+        /// <param name="excludedClientIds"></param>
+        /// <param name="use"><see cref="RpcTargetUse.Temp"/> will return a cached target, which should not be stored as it will
+        /// be overwritten in future calls to Not() or Group(). Do not call Dispose() on Temp targets.<br /><br /><see cref="RpcTargetUse.Persistent"/> will
+        /// return a new target, which can be stored, but should not be done frequently because it results in a GC allocation. You must call Dispose() on Persistent targets when you are done with them.</param>
+        /// <returns></returns>
+        public BaseRpcTarget Not(NativeArray<ulong> excludedClientIds, RpcTargetUse use)
+        {
+            IGroupRpcTarget target;
+            if (m_NetworkManager.IsServer)
+            {
+                if (use == RpcTargetUse.Persistent)
+                {
+                    target = new RpcTargetGroup(m_NetworkManager);
+                }
+                else
+                {
+                    target = m_CachedTargetGroup;
+                }
+            }
+            else
+            {
+                if (use == RpcTargetUse.Persistent)
+                {
+                    target = new ProxyRpcTargetGroup(m_NetworkManager);
+                }
+                else
+                {
+                    target = m_CachedProxyRpcTargetGroup;
+                }
+            }
+            target.Clear();
+
+            using var asASet = new NativeHashSet<ulong>(excludedClientIds.Length, Allocator.Temp);
+            foreach (var clientId in excludedClientIds)
+            {
+                asASet.Add(clientId);
+            }
+
+            foreach (var clientId in m_NetworkManager.ConnectedClientsIds)
+            {
+                if (!asASet.Contains(clientId))
+                {
+                    target.Add(clientId);
+                }
+            }
+
+            // If ServerIsHost, ConnectedClientIds already contains ServerClientId and this would duplicate it.
+            if (!m_NetworkManager.ServerIsHost && !asASet.Contains(NetworkManager.ServerClientId))
+            {
+                target.Add(NetworkManager.ServerClientId);
+            }
+
+            return target.Target;
+        }
+
+        /// <summary>
+        /// Sends to everyone EXCEPT a group of client IDs.
+        /// NativeList can be trivially constructed using Allocator.Temp, making this an efficient
+        /// Group method if the group list is dynamically constructed.
+        /// </summary>
+        /// <param name="excludedClientIds"></param>
+        /// <param name="use"><see cref="RpcTargetUse.Temp"/> will return a cached target, which should not be stored as it will
+        /// be overwritten in future calls to Not() or Group(). Do not call Dispose() on Temp targets.<br /><br /><see cref="RpcTargetUse.Persistent"/> will
+        /// return a new target, which can be stored, but should not be done frequently because it results in a GC allocation. You must call Dispose() on Persistent targets when you are done with them.</param>
+        /// <returns></returns>
+        public BaseRpcTarget Not(NativeList<ulong> excludedClientIds, RpcTargetUse use)
+        {
+            var asArray = excludedClientIds.AsArray();
+            return Not(asArray, use);
+        }
+
+        /// <summary>
+        /// Sends to everyone EXCEPT a group of client IDs.
+        /// Constructing arrays requires garbage collected allocations. This override is only recommended
+        /// if you either have no strict performance requirements, or have the group of client IDs cached so
+        /// it is not created each time.
+        /// </summary>
+        /// <param name="excludedClientIds"></param>
+        /// <param name="use"><see cref="RpcTargetUse.Temp"/> will return a cached target, which should not be stored as it will
+        /// be overwritten in future calls to Not() or Group(). Do not call Dispose() on Temp targets.<br /><br /><see cref="RpcTargetUse.Persistent"/> will
+        /// return a new target, which can be stored, but should not be done frequently because it results in a GC allocation. You must call Dispose() on Persistent targets when you are done with them.</param>
+        /// <returns></returns>
+        public BaseRpcTarget Not(ulong[] excludedClientIds, RpcTargetUse use)
+        {
+            return Not(new NativeArray<ulong>(excludedClientIds, Allocator.Temp), use);
+        }
+
+        /// <summary>
+        /// Sends to everyone EXCEPT a group of client IDs.
+        /// This accepts any IEnumerable type, such as List&lt;ulong&gt;, but cannot be called without
+        /// a garbage collected allocation (even if the type itself is a struct type, due to boxing).
+        /// This override is only recommended if you either have no strict performance requirements,
+        /// or have the group of client IDs cached so it is not created each time.
+        /// </summary>
+        /// <param name="excludedClientIds"></param>
+        /// <param name="use"><see cref="RpcTargetUse.Temp"/> will return a cached target, which should not be stored as it will
+        /// be overwritten in future calls to Not() or Group(). Do not call Dispose() on Temp targets.<br /><br /><see cref="RpcTargetUse.Persistent"/> will
+        /// return a new target, which can be stored, but should not be done frequently because it results in a GC allocation. You must call Dispose() on Persistent targets when you are done with them.</param>
+        /// <returns></returns>
+        public BaseRpcTarget Not<T>(T excludedClientIds, RpcTargetUse use) where T : IEnumerable<ulong>
+        {
+            IGroupRpcTarget target;
+            if (m_NetworkManager.IsServer)
+            {
+                if (use == RpcTargetUse.Persistent)
+                {
+                    target = new RpcTargetGroup(m_NetworkManager);
+                }
+                else
+                {
+                    target = m_CachedTargetGroup;
+                }
+            }
+            else
+            {
+                if (use == RpcTargetUse.Persistent)
+                {
+                    target = new ProxyRpcTargetGroup(m_NetworkManager);
+                }
+                else
+                {
+                    target = m_CachedProxyRpcTargetGroup;
+                }
+            }
+            target.Clear();
+
+            using var asASet = new NativeHashSet<ulong>(m_NetworkManager.ConnectedClientsIds.Count, Allocator.Temp);
+            foreach (var clientId in excludedClientIds)
+            {
+                asASet.Add(clientId);
+            }
+
+            foreach (var clientId in m_NetworkManager.ConnectedClientsIds)
+            {
+                if (!asASet.Contains(clientId))
+                {
+                    target.Add(clientId);
+                }
+            }
+
+            // If ServerIsHost, ConnectedClientIds already contains ServerClientId and this would duplicate it.
+            if (!m_NetworkManager.ServerIsHost && !asASet.Contains(NetworkManager.ServerClientId))
+            {
+                target.Add(NetworkManager.ServerClientId);
+            }
+
+            return target.Target;
+        }
+
+        private ProxyRpcTargetGroup m_CachedProxyRpcTargetGroup;
+        private RpcTargetGroup m_CachedTargetGroup;
+        private DirectSendRpcTarget m_CachedDirectSendTarget;
+        private ProxyRpcTarget m_CachedProxyRpcTarget;
+    }
+}

Runtime/Messaging/RpcTargets/RpcTarget.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: 1b26d0227e71408b918ae25ca2a0179b
+timeCreated: 1699555535

Runtime/Messaging/RpcTargets/RpcTargetGroup.cs

@@ -0,0 +1,80 @@
+using System.Collections.Generic;
+
+namespace Unity.Netcode
+{
+    internal class RpcTargetGroup : BaseRpcTarget, IGroupRpcTarget
+    {
+        public BaseRpcTarget Target => this;
+
+        internal List<BaseRpcTarget> Targets = new List<BaseRpcTarget>();
+
+        private LocalSendRpcTarget m_LocalSendRpcTarget;
+        private HashSet<ulong> m_Ids = new HashSet<ulong>();
+        private Stack<DirectSendRpcTarget> m_TargetCache = new Stack<DirectSendRpcTarget>();
+
+        public override void Dispose()
+        {
+            CheckLockBeforeDispose();
+            foreach (var target in Targets)
+            {
+                target.Dispose();
+            }
+            foreach (var target in m_TargetCache)
+            {
+                target.Dispose();
+            }
+            m_LocalSendRpcTarget.Dispose();
+        }
+
+        internal override void Send(NetworkBehaviour behaviour, ref RpcMessage message, NetworkDelivery delivery, RpcParams rpcParams)
+        {
+            foreach (var target in Targets)
+            {
+                target.Send(behaviour, ref message, delivery, rpcParams);
+            }
+        }
+
+        public void Add(ulong clientId)
+        {
+            if (!m_Ids.Contains(clientId))
+            {
+                m_Ids.Add(clientId);
+                if (clientId == m_NetworkManager.LocalClientId)
+                {
+                    Targets.Add(m_LocalSendRpcTarget);
+                }
+                else
+                {
+                    if (m_TargetCache.Count == 0)
+                    {
+                        Targets.Add(new DirectSendRpcTarget(m_NetworkManager) { ClientId = clientId });
+                    }
+                    else
+                    {
+                        var target = m_TargetCache.Pop();
+                        target.ClientId = clientId;
+                        Targets.Add(target);
+                    }
+                }
+            }
+        }
+
+        public void Clear()
+        {
+            m_Ids.Clear();
+            foreach (var target in Targets)
+            {
+                if (target is DirectSendRpcTarget directSendRpcTarget)
+                {
+                    m_TargetCache.Push(directSendRpcTarget);
+                }
+            }
+            Targets.Clear();
+        }
+
+        internal RpcTargetGroup(NetworkManager manager) : base(manager)
+        {
+            m_LocalSendRpcTarget = new LocalSendRpcTarget(manager);
+        }
+    }
+}

Runtime/Messaging/RpcTargets/RpcTargetGroup.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: 7f8c0fc053b64a588c99dd7d706d9f0a
+timeCreated: 1697824991

Runtime/Messaging/RpcTargets/ServerRpcTarget.cs

@@ -0,0 +1,42 @@
+namespace Unity.Netcode
+{
+    internal class ServerRpcTarget : BaseRpcTarget
+    {
+        protected BaseRpcTarget m_UnderlyingTarget;
+
+        public override void Dispose()
+        {
+            if (m_UnderlyingTarget != null)
+            {
+                m_UnderlyingTarget.Dispose();
+                m_UnderlyingTarget = null;
+            }
+        }
+
+        internal override void Send(NetworkBehaviour behaviour, ref RpcMessage message, NetworkDelivery delivery, RpcParams rpcParams)
+        {
+            if (behaviour.NetworkManager.DistributedAuthorityMode && behaviour.NetworkManager.CMBServiceConnection)
+            {
+                UnityEngine.Debug.LogWarning("[Invalid Target] There is no server to send to when in Distributed Authority mode!");
+                return;
+            }
+
+            if (m_UnderlyingTarget == null)
+            {
+                if (behaviour.NetworkManager.IsServer)
+                {
+                    m_UnderlyingTarget = new LocalSendRpcTarget(m_NetworkManager);
+                }
+                else
+                {
+                    m_UnderlyingTarget = new DirectSendRpcTarget(m_NetworkManager) { ClientId = NetworkManager.ServerClientId };
+                }
+            }
+            m_UnderlyingTarget.Send(behaviour, ref message, delivery, rpcParams);
+        }
+
+        internal ServerRpcTarget(NetworkManager manager) : base(manager)
+        {
+        }
+    }
+}

Runtime/Messaging/RpcTargets/ServerRpcTarget.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: c911725afb6d44f3bb1a1d567d9dee0f
+timeCreated: 1697824979

Runtime/NetworkVariable/CollectionSerializationUtility.cs

@@ -0,0 +1,769 @@
+using System;
+using System.Collections.Generic;
+using Unity.Collections;
+using Unity.Collections.LowLevel.Unsafe;
+using Unity.Mathematics;
+
+namespace Unity.Netcode
+{
+    internal static class CollectionSerializationUtility
+    {
+        public static void WriteNativeArrayDelta<T>(FastBufferWriter writer, ref NativeArray<T> value, ref NativeArray<T> previousValue) where T : unmanaged
+        {
+            // This bit vector serializes the list of which fields have changed using 1 bit per field.
+            // This will always be 1 bit per field of the whole array (rounded up to the nearest 8 bits)
+            // even if there is only one change, so as compared to serializing the index with each item,
+            // this will use more bandwidth when the overall bandwidth usage is small and the array is large,
+            // but less when the overall bandwidth usage is large. So it optimizes for the worst case while accepting
+            // some reduction in efficiency in the best case.
+            using var changes = new ResizableBitVector(Allocator.Temp);
+            int minLength = math.min(value.Length, previousValue.Length);
+            var numChanges = 0;
+            // Iterate the array, checking which values have changed and marking that in the bit vector
+            for (var i = 0; i < minLength; ++i)
+            {
+                var val = value[i];
+                var prevVal = previousValue[i];
+                if (!NetworkVariableSerialization<T>.AreEqual(ref val, ref prevVal))
+                {
+                    ++numChanges;
+                    changes.Set(i);
+                }
+            }
+
+            // Mark any newly added items as well
+            // We don't need to mark removed items because they are captured by serializing the length
+            for (var i = previousValue.Length; i < value.Length; ++i)
+            {
+                ++numChanges;
+                changes.Set(i);
+            }
+
+            // If the size of serializing the dela is greater than the size of serializing the whole array (i.e.,
+            // because almost the entire array has changed and the overhead of the change set increases bandwidth),
+            // then we just do a normal full serialization instead of a delta.
+            if (changes.GetSerializedSize() + FastBufferWriter.GetWriteSize<T>() * numChanges > FastBufferWriter.GetWriteSize<T>() * value.Length)
+            {
+                // 1 = full serialization
+                writer.WriteByteSafe(1);
+                writer.WriteValueSafe(value);
+                return;
+            }
+            // 0 = delta serialization
+            writer.WriteByte(0);
+            // Write the length, which will be used on the read side to resize the array
+            BytePacker.WriteValuePacked(writer, value.Length);
+            writer.WriteValueSafe(changes);
+            unsafe
+            {
+                var ptr = (T*)value.GetUnsafePtr();
+                var prevPtr = (T*)previousValue.GetUnsafePtr();
+                for (int i = 0; i < value.Length; ++i)
+                {
+                    if (changes.IsSet(i))
+                    {
+                        if (i < previousValue.Length)
+                        {
+                            // If we have an item in the previous array for this index, we can do nested deltas!
+                            NetworkVariableSerialization<T>.WriteDelta(writer, ref ptr[i], ref prevPtr[i]);
+                        }
+                        else
+                        {
+                            // If not, just write it normally
+                            NetworkVariableSerialization<T>.Write(writer, ref ptr[i]);
+                        }
+                    }
+                }
+            }
+        }
+        public static void ReadNativeArrayDelta<T>(FastBufferReader reader, ref NativeArray<T> value) where T : unmanaged
+        {
+            // 1 = full serialization, 0 = delta serialization
+            reader.ReadByteSafe(out byte full);
+            if (full == 1)
+            {
+                // If we're doing full serialization, we fall back on reading the whole array.
+                value.Dispose();
+                reader.ReadValueSafe(out value, Allocator.Persistent);
+                return;
+            }
+            // If not, first read the length and the change bits
+            ByteUnpacker.ReadValuePacked(reader, out int length);
+            var changes = new ResizableBitVector(Allocator.Temp);
+            using var toDispose = changes;
+            {
+                reader.ReadNetworkSerializableInPlace(ref changes);
+
+                // If the length has changed, we need to resize.
+                // NativeArray is not resizeable, so we have to dispose and allocate a new one.
+                var previousLength = value.Length;
+                if (length != value.Length)
+                {
+                    var newArray = new NativeArray<T>(length, Allocator.Persistent);
+                    unsafe
+                    {
+                        UnsafeUtility.MemCpy(newArray.GetUnsafePtr(), value.GetUnsafePtr(), math.min(newArray.Length * sizeof(T), value.Length * sizeof(T)));
+                    }
+                    value.Dispose();
+                    value = newArray;
+                }
+
+                unsafe
+                {
+                    var ptr = (T*)value.GetUnsafePtr();
+                    for (var i = 0; i < value.Length; ++i)
+                    {
+                        if (changes.IsSet(i))
+                        {
+                            if (i < previousLength)
+                            {
+                                // If we have an item to read a delta into, read it as a delta
+                                NetworkVariableSerialization<T>.ReadDelta(reader, ref ptr[i]);
+                            }
+                            else
+                            {
+                                // If not, read as a standard element
+                                NetworkVariableSerialization<T>.Read(reader, ref ptr[i]);
+                            }
+                        }
+                    }
+                }
+            }
+        }
+        public static void WriteListDelta<T>(FastBufferWriter writer, ref List<T> value, ref List<T> previousValue)
+        {
+            // Lists can be null, so we have to handle that case.
+            // We do that by marking this as a full serialization and using the existing null handling logic
+            // in NetworkVariableSerialization<List<T>>
+            if (value == null || previousValue == null)
+            {
+                writer.WriteByteSafe(1);
+                NetworkVariableSerialization<List<T>>.Write(writer, ref value);
+                return;
+            }
+            // This bit vector serializes the list of which fields have changed using 1 bit per field.
+            // This will always be 1 bit per field of the whole array (rounded up to the nearest 8 bits)
+            // even if there is only one change, so as compared to serializing the index with each item,
+            // this will use more bandwidth when the overall bandwidth usage is small and the array is large,
+            // but less when the overall bandwidth usage is large. So it optimizes for the worst case while accepting
+            // some reduction in efficiency in the best case.
+            using var changes = new ResizableBitVector(Allocator.Temp);
+            int minLength = math.min(value.Count, previousValue.Count);
+            var numChanges = 0;
+            // Iterate the list, checking which values have changed and marking that in the bit vector
+            for (var i = 0; i < minLength; ++i)
+            {
+                var val = value[i];
+                var prevVal = previousValue[i];
+                if (!NetworkVariableSerialization<T>.AreEqual(ref val, ref prevVal))
+                {
+                    ++numChanges;
+                    changes.Set(i);
+                }
+            }
+
+            // Mark any newly added items as well
+            // We don't need to mark removed items because they are captured by serializing the length
+            for (var i = previousValue.Count; i < value.Count; ++i)
+            {
+                ++numChanges;
+                changes.Set(i);
+            }
+
+            // If the size of serializing the dela is greater than the size of serializing the whole array (i.e.,
+            // because almost the entire array has changed and the overhead of the change set increases bandwidth),
+            // then we just do a normal full serialization instead of a delta.
+            // In the case of List<T>, it's difficult to know exactly what the serialized size is going to be before
+            // we serialize it, so we fudge it.
+            if (numChanges >= value.Count * 0.9)
+            {
+                // 1 = full serialization
+                writer.WriteByteSafe(1);
+                NetworkVariableSerialization<List<T>>.Write(writer, ref value);
+                return;
+            }
+
+            // 0 = delta serialization
+            writer.WriteByteSafe(0);
+            // Write the length, which will be used on the read side to resize the list
+            BytePacker.WriteValuePacked(writer, value.Count);
+            writer.WriteValueSafe(changes);
+            for (int i = 0; i < value.Count; ++i)
+            {
+                if (changes.IsSet(i))
+                {
+                    var reffable = value[i];
+                    if (i < previousValue.Count)
+                    {
+                        // If we have an item in the previous array for this index, we can do nested deltas!
+                        var prevReffable = previousValue[i];
+                        NetworkVariableSerialization<T>.WriteDelta(writer, ref reffable, ref prevReffable);
+                    }
+                    else
+                    {
+                        // If not, just write it normally.
+                        NetworkVariableSerialization<T>.Write(writer, ref reffable);
+                    }
+                }
+            }
+        }
+        public static void ReadListDelta<T>(FastBufferReader reader, ref List<T> value)
+        {
+            // 1 = full serialization, 0 = delta serialization
+            reader.ReadByteSafe(out byte full);
+            if (full == 1)
+            {
+                // If we're doing full serialization, we fall back on reading the whole list.
+                NetworkVariableSerialization<List<T>>.Read(reader, ref value);
+                return;
+            }
+            // If not, first read the length and the change bits
+            ByteUnpacker.ReadValuePacked(reader, out int length);
+            var changes = new ResizableBitVector(Allocator.Temp);
+            using var toDispose = changes;
+            {
+                reader.ReadNetworkSerializableInPlace(ref changes);
+
+                // If the list shrank, we need to resize it down.
+                // List<T> has no method to reserve space for future elements,
+                // so if we have to grow it, we just do that using Add() below.
+                if (length < value.Count)
+                {
+                    value.RemoveRange(length, value.Count - length);
+                }
+
+                for (var i = 0; i < length; ++i)
+                {
+                    if (changes.IsSet(i))
+                    {
+                        if (i < value.Count)
+                        {
+                            // If we have an item to read a delta into, read it as a delta
+                            T item = value[i];
+                            NetworkVariableSerialization<T>.ReadDelta(reader, ref item);
+                            value[i] = item;
+                        }
+                        else
+                        {
+                            // If not, just read it as a standard item.
+                            T item = default;
+                            NetworkVariableSerialization<T>.Read(reader, ref item);
+                            value.Add(item);
+                        }
+                    }
+                }
+            }
+        }
+
+        // For HashSet and Dictionary, we need to have some local space to hold lists we need to serialize.
+        // We don't want to do allocations all the time and we know each one needs a maximum of three lists,
+        // so we're going to keep static lists that we can reuse in these methods.
+        private static class ListCache<T>
+        {
+            private static List<T> s_AddedList = new List<T>();
+            private static List<T> s_RemovedList = new List<T>();
+            private static List<T> s_ChangedList = new List<T>();
+
+            public static List<T> GetAddedList()
+            {
+                s_AddedList.Clear();
+                return s_AddedList;
+            }
+            public static List<T> GetRemovedList()
+            {
+                s_RemovedList.Clear();
+                return s_RemovedList;
+            }
+            public static List<T> GetChangedList()
+            {
+                s_ChangedList.Clear();
+                return s_ChangedList;
+            }
+        }
+
+        public static void WriteHashSetDelta<T>(FastBufferWriter writer, ref HashSet<T> value, ref HashSet<T> previousValue) where T : IEquatable<T>
+        {
+            // HashSets can be null, so we have to handle that case.
+            // We do that by marking this as a full serialization and using the existing null handling logic
+            // in NetworkVariableSerialization<HashSet<T>>
+            if (value == null || previousValue == null)
+            {
+                writer.WriteByteSafe(1);
+                NetworkVariableSerialization<HashSet<T>>.Write(writer, ref value);
+                return;
+            }
+            // No changed array because a set can't have a "changed" element, only added and removed.
+            var added = ListCache<T>.GetAddedList();
+            var removed = ListCache<T>.GetRemovedList();
+            // collect the new elements
+            foreach (var item in value)
+            {
+                if (!previousValue.Contains(item))
+                {
+                    added.Add(item);
+                }
+            }
+
+            // collect the removed elements
+            foreach (var item in previousValue)
+            {
+                if (!value.Contains(item))
+                {
+                    removed.Add(item);
+                }
+            }
+
+            // If we've got more changes than total items, we just do a full serialization
+            if (added.Count + removed.Count >= value.Count)
+            {
+                writer.WriteByteSafe(1);
+                NetworkVariableSerialization<HashSet<T>>.Write(writer, ref value);
+                return;
+            }
+
+            writer.WriteByteSafe(0);
+            // Write out the added and removed arrays.
+            writer.WriteValueSafe(added.Count);
+            for (var i = 0; i < added.Count; ++i)
+            {
+                var item = added[i];
+                NetworkVariableSerialization<T>.Write(writer, ref item);
+            }
+            writer.WriteValueSafe(removed.Count);
+            for (var i = 0; i < removed.Count; ++i)
+            {
+                var item = removed[i];
+                NetworkVariableSerialization<T>.Write(writer, ref item);
+            }
+        }
+
+        public static void ReadHashSetDelta<T>(FastBufferReader reader, ref HashSet<T> value) where T : IEquatable<T>
+        {
+            // 1 = full serialization, 0 = delta serialization
+            reader.ReadByteSafe(out byte full);
+            if (full != 0)
+            {
+                NetworkVariableSerialization<HashSet<T>>.Read(reader, ref value);
+                return;
+            }
+            // Read in the added and removed values
+            reader.ReadValueSafe(out int addedCount);
+            for (var i = 0; i < addedCount; ++i)
+            {
+                T item = default;
+                NetworkVariableSerialization<T>.Read(reader, ref item);
+                value.Add(item);
+            }
+            reader.ReadValueSafe(out int removedCount);
+            for (var i = 0; i < removedCount; ++i)
+            {
+                T item = default;
+                NetworkVariableSerialization<T>.Read(reader, ref item);
+                value.Remove(item);
+            }
+        }
+        public static void WriteDictionaryDelta<TKey, TVal>(FastBufferWriter writer, ref Dictionary<TKey, TVal> value, ref Dictionary<TKey, TVal> previousValue)
+            where TKey : IEquatable<TKey>
+        {
+            if (value == null || previousValue == null)
+            {
+                writer.WriteByteSafe(1);
+                NetworkVariableSerialization<Dictionary<TKey, TVal>>.Write(writer, ref value);
+                return;
+            }
+            var added = ListCache<KeyValuePair<TKey, TVal>>.GetAddedList();
+            var changed = ListCache<KeyValuePair<TKey, TVal>>.GetRemovedList();
+            var removed = ListCache<KeyValuePair<TKey, TVal>>.GetChangedList();
+            // Collect items that have been added or have changed
+            foreach (var item in value)
+            {
+                var val = item.Value;
+                var hasPrevVal = previousValue.TryGetValue(item.Key, out var prevVal);
+                if (!hasPrevVal)
+                {
+                    added.Add(item);
+                }
+                else if (!NetworkVariableSerialization<TVal>.AreEqual(ref val, ref prevVal))
+                {
+                    changed.Add(item);
+                }
+            }
+
+            // collect the items that have been removed
+            foreach (var item in previousValue)
+            {
+                if (!value.ContainsKey(item.Key))
+                {
+                    removed.Add(item);
+                }
+            }
+
+            // If there are more changes than total values, just do a full serialization
+            if (added.Count + removed.Count + changed.Count >= value.Count)
+            {
+                writer.WriteByteSafe(1);
+                NetworkVariableSerialization<Dictionary<TKey, TVal>>.Write(writer, ref value);
+                return;
+            }
+
+            writer.WriteByteSafe(0);
+            // Else, write out the added, removed, and changed arrays
+            writer.WriteValueSafe(added.Count);
+            for (var i = 0; i < added.Count; ++i)
+            {
+                (var key, var val) = (added[i].Key, added[i].Value);
+                NetworkVariableSerialization<TKey>.Write(writer, ref key);
+                NetworkVariableSerialization<TVal>.Write(writer, ref val);
+            }
+            writer.WriteValueSafe(removed.Count);
+            for (var i = 0; i < removed.Count; ++i)
+            {
+                var key = removed[i].Key;
+                NetworkVariableSerialization<TKey>.Write(writer, ref key);
+            }
+            writer.WriteValueSafe(changed.Count);
+            for (var i = 0; i < changed.Count; ++i)
+            {
+                (var key, var val) = (changed[i].Key, changed[i].Value);
+                NetworkVariableSerialization<TKey>.Write(writer, ref key);
+                NetworkVariableSerialization<TVal>.Write(writer, ref val);
+            }
+        }
+
+        public static void ReadDictionaryDelta<TKey, TVal>(FastBufferReader reader, ref Dictionary<TKey, TVal> value)
+            where TKey : IEquatable<TKey>
+        {
+            // 1 = full serialization, 0 = delta serialization
+            reader.ReadByteSafe(out byte full);
+            if (full != 0)
+            {
+                NetworkVariableSerialization<Dictionary<TKey, TVal>>.Read(reader, ref value);
+                return;
+            }
+            // Added
+            reader.ReadValueSafe(out int length);
+            for (var i = 0; i < length; ++i)
+            {
+                (TKey key, TVal val) = (default, default);
+                NetworkVariableSerialization<TKey>.Read(reader, ref key);
+                NetworkVariableSerialization<TVal>.Read(reader, ref val);
+                value.Add(key, val);
+            }
+            // Removed
+            reader.ReadValueSafe(out length);
+            for (var i = 0; i < length; ++i)
+            {
+                TKey key = default;
+                NetworkVariableSerialization<TKey>.Read(reader, ref key);
+                value.Remove(key);
+            }
+            // Changed
+            reader.ReadValueSafe(out length);
+            for (var i = 0; i < length; ++i)
+            {
+                (TKey key, TVal val) = (default, default);
+                NetworkVariableSerialization<TKey>.Read(reader, ref key);
+                NetworkVariableSerialization<TVal>.Read(reader, ref val);
+                value[key] = val;
+            }
+        }
+
+#if UNITY_NETCODE_NATIVE_COLLECTION_SUPPORT
+        public static void WriteNativeListDelta<T>(FastBufferWriter writer, ref NativeList<T> value, ref NativeList<T> previousValue) where T : unmanaged
+        {
+            // See WriteListDelta and WriteNativeArrayDelta to understand most of this. It's basically the same,
+            // just adjusted for the NativeList API
+            using var changes = new ResizableBitVector(Allocator.Temp);
+            int minLength = math.min(value.Length, previousValue.Length);
+            var numChanges = 0;
+            for (var i = 0; i < minLength; ++i)
+            {
+                var val = value[i];
+                var prevVal = previousValue[i];
+                if (!NetworkVariableSerialization<T>.AreEqual(ref val, ref prevVal))
+                {
+                    ++numChanges;
+                    changes.Set(i);
+                }
+            }
+
+            for (var i = previousValue.Length; i < value.Length; ++i)
+            {
+                ++numChanges;
+                changes.Set(i);
+            }
+
+            if (changes.GetSerializedSize() + FastBufferWriter.GetWriteSize<T>() * numChanges > FastBufferWriter.GetWriteSize<T>() * value.Length)
+            {
+                writer.WriteByteSafe(1);
+                writer.WriteValueSafe(value);
+                return;
+            }
+
+            writer.WriteByte(0);
+            BytePacker.WriteValuePacked(writer, value.Length);
+            writer.WriteValueSafe(changes);
+            unsafe
+            {
+#if UTP_TRANSPORT_2_0_ABOVE
+                var ptr = value.GetUnsafePtr();
+                var prevPtr = previousValue.GetUnsafePtr();
+#else
+                var ptr = (T*)value.GetUnsafePtr();
+                var prevPtr = (T*)previousValue.GetUnsafePtr();
+#endif
+                for (int i = 0; i < value.Length; ++i)
+                {
+                    if (changes.IsSet(i))
+                    {
+                        if (i < previousValue.Length)
+                        {
+                            NetworkVariableSerialization<T>.WriteDelta(writer, ref ptr[i], ref prevPtr[i]);
+                        }
+                        else
+                        {
+                            NetworkVariableSerialization<T>.Write(writer, ref ptr[i]);
+                        }
+                    }
+                }
+            }
+        }
+        public static void ReadNativeListDelta<T>(FastBufferReader reader, ref NativeList<T> value) where T : unmanaged
+        {
+            // See ReadListDelta and ReadNativeArrayDelta to understand most of this. It's basically the same,
+            // just adjusted for the NativeList API
+            reader.ReadByteSafe(out byte full);
+            if (full == 1)
+            {
+                reader.ReadValueSafeInPlace(ref value);
+                return;
+            }
+            ByteUnpacker.ReadValuePacked(reader, out int length);
+            var changes = new ResizableBitVector(Allocator.Temp);
+            using var toDispose = changes;
+            {
+                reader.ReadNetworkSerializableInPlace(ref changes);
+
+                var previousLength = value.Length;
+                // The one big difference between this and NativeArray/List is that NativeList supports
+                // easy and fast resizing and reserving space.
+                if (length != value.Length)
+                {
+                    value.Resize(length, NativeArrayOptions.UninitializedMemory);
+                }
+
+                unsafe
+                {
+#if UTP_TRANSPORT_2_0_ABOVE
+                    var ptr = value.GetUnsafePtr();
+#else
+                    var ptr = (T*)value.GetUnsafePtr();
+#endif
+                    for (var i = 0; i < value.Length; ++i)
+                    {
+                        if (changes.IsSet(i))
+                        {
+                            if (i < previousLength)
+                            {
+                                NetworkVariableSerialization<T>.ReadDelta(reader, ref ptr[i]);
+                            }
+                            else
+                            {
+                                NetworkVariableSerialization<T>.Read(reader, ref ptr[i]);
+                            }
+                        }
+                    }
+                }
+            }
+        }
+
+        public static unsafe void WriteNativeHashSetDelta<T>(FastBufferWriter writer, ref NativeHashSet<T> value, ref NativeHashSet<T> previousValue) where T : unmanaged, IEquatable<T>
+        {
+            // See WriteHashSet; this is the same algorithm, adjusted for the NativeHashSet API
+            var added = stackalloc T[value.Count];
+            var removed = stackalloc T[previousValue.Count];
+            var addedCount = 0;
+            var removedCount = 0;
+            foreach (var item in value)
+            {
+                if (!previousValue.Contains(item))
+                {
+                    added[addedCount] = item;
+                    ++addedCount;
+                }
+            }
+
+            foreach (var item in previousValue)
+            {
+                if (!value.Contains(item))
+                {
+                    removed[removedCount] = item;
+                    ++removedCount;
+                }
+            }
+#if UTP_TRANSPORT_2_0_ABOVE
+            if (addedCount + removedCount >= value.Count)
+#else
+            if (addedCount + removedCount >= value.Count())
+#endif
+            {
+                writer.WriteByteSafe(1);
+                writer.WriteValueSafe(value);
+                return;
+            }
+
+            writer.WriteByteSafe(0);
+            writer.WriteValueSafe(addedCount);
+            for (var i = 0; i < addedCount; ++i)
+            {
+                NetworkVariableSerialization<T>.Write(writer, ref added[i]);
+            }
+            writer.WriteValueSafe(removedCount);
+            for (var i = 0; i < removedCount; ++i)
+            {
+                NetworkVariableSerialization<T>.Write(writer, ref removed[i]);
+            }
+        }
+
+        public static void ReadNativeHashSetDelta<T>(FastBufferReader reader, ref NativeHashSet<T> value) where T : unmanaged, IEquatable<T>
+        {
+            // See ReadHashSet; this is the same algorithm, adjusted for the NativeHashSet API
+            reader.ReadByteSafe(out byte full);
+            if (full != 0)
+            {
+                reader.ReadValueSafeInPlace(ref value);
+                return;
+            }
+            reader.ReadValueSafe(out int addedCount);
+            for (var i = 0; i < addedCount; ++i)
+            {
+                T item = default;
+                NetworkVariableSerialization<T>.Read(reader, ref item);
+                value.Add(item);
+            }
+            reader.ReadValueSafe(out int removedCount);
+            for (var i = 0; i < removedCount; ++i)
+            {
+                T item = default;
+                NetworkVariableSerialization<T>.Read(reader, ref item);
+                value.Remove(item);
+            }
+        }
+
+        public static unsafe void WriteNativeHashMapDelta<TKey, TVal>(FastBufferWriter writer, ref NativeHashMap<TKey, TVal> value, ref NativeHashMap<TKey, TVal> previousValue)
+            where TKey : unmanaged, IEquatable<TKey>
+            where TVal : unmanaged
+        {
+            // See WriteDictionary; this is the same algorithm, adjusted for the NativeHashMap API
+#if UTP_TRANSPORT_2_0_ABOVE
+            var added = stackalloc KVPair<TKey, TVal>[value.Count];
+            var changed = stackalloc KVPair<TKey, TVal>[value.Count];
+            var removed = stackalloc KVPair<TKey, TVal>[previousValue.Count];
+#else
+            var added = stackalloc KeyValue<TKey, TVal>[value.Count()];
+            var changed = stackalloc KeyValue<TKey, TVal>[value.Count()];
+            var removed = stackalloc KeyValue<TKey, TVal>[previousValue.Count()];
+#endif
+            var addedCount = 0;
+            var changedCount = 0;
+            var removedCount = 0;
+            foreach (var item in value)
+            {
+
+                var hasPrevVal = previousValue.TryGetValue(item.Key, out var prevVal);
+                if (!hasPrevVal)
+                {
+                    added[addedCount] = item;
+                    ++addedCount;
+                }
+                else if (!NetworkVariableSerialization<TVal>.AreEqual(ref item.Value, ref prevVal))
+                {
+                    changed[changedCount] = item;
+                    ++changedCount;
+                }
+            }
+
+            foreach (var item in previousValue)
+            {
+                if (!value.ContainsKey(item.Key))
+                {
+                    removed[removedCount] = item;
+                    ++removedCount;
+                }
+            }
+
+#if UTP_TRANSPORT_2_0_ABOVE
+            if (addedCount + removedCount + changedCount >= value.Count)
+#else
+            if (addedCount + removedCount + changedCount >= value.Count())
+#endif
+            {
+                writer.WriteByteSafe(1);
+                writer.WriteValueSafe(value);
+                return;
+            }
+
+            writer.WriteByteSafe(0);
+            writer.WriteValueSafe(addedCount);
+            for (var i = 0; i < addedCount; ++i)
+            {
+                (var key, var val) = (added[i].Key, added[i].Value);
+                NetworkVariableSerialization<TKey>.Write(writer, ref key);
+                NetworkVariableSerialization<TVal>.Write(writer, ref val);
+            }
+            writer.WriteValueSafe(removedCount);
+            for (var i = 0; i < removedCount; ++i)
+            {
+                var key = removed[i].Key;
+                NetworkVariableSerialization<TKey>.Write(writer, ref key);
+            }
+            writer.WriteValueSafe(changedCount);
+            for (var i = 0; i < changedCount; ++i)
+            {
+                (var key, var val) = (changed[i].Key, changed[i].Value);
+                NetworkVariableSerialization<TKey>.Write(writer, ref key);
+                NetworkVariableSerialization<TVal>.Write(writer, ref val);
+            }
+        }
+
+        public static void ReadNativeHashMapDelta<TKey, TVal>(FastBufferReader reader, ref NativeHashMap<TKey, TVal> value)
+            where TKey : unmanaged, IEquatable<TKey>
+            where TVal : unmanaged
+        {
+            // See ReadDictionary; this is the same algorithm, adjusted for the NativeHashMap API
+            reader.ReadByteSafe(out byte full);
+            if (full != 0)
+            {
+                reader.ReadValueSafeInPlace(ref value);
+                return;
+            }
+            // Added
+            reader.ReadValueSafe(out int length);
+            for (var i = 0; i < length; ++i)
+            {
+                (TKey key, TVal val) = (default, default);
+                NetworkVariableSerialization<TKey>.Read(reader, ref key);
+                NetworkVariableSerialization<TVal>.Read(reader, ref val);
+                value.Add(key, val);
+            }
+            // Removed
+            reader.ReadValueSafe(out length);
+            for (var i = 0; i < length; ++i)
+            {
+                TKey key = default;
+                NetworkVariableSerialization<TKey>.Read(reader, ref key);
+                value.Remove(key);
+            }
+            // Changed
+            reader.ReadValueSafe(out length);
+            for (var i = 0; i < length; ++i)
+            {
+                (TKey key, TVal val) = (default, default);
+                NetworkVariableSerialization<TKey>.Read(reader, ref key);
+                NetworkVariableSerialization<TVal>.Read(reader, ref val);
+                value[key] = val;
+            }
+        }
+#endif
+    }
+}

Runtime/NetworkVariable/CollectionSerializationUtility.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: c822ece4e24f4676861e07288a7f8526
+timeCreated: 1705437250