com.unity.netcode.gameobjects@1.0.0-pre.7

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).

## [1.0.0-pre.7] - 2022-04-01

### Added

- Added editor only check prior to entering into play mode if the currently open and active scene is in the build list and if not displays a dialog box asking the user if they would like to automatically add it prior to entering into play mode. (#1828)
- Added `UnityTransport` implementation and `com.unity.transport` package dependency (#1823)
- Added `NetworkVariableWritePermission` to `NetworkVariableBase` and implemented `Owner` client writable netvars. (#1762)
- `UnityTransport` settings can now be set programmatically. (#1845)
- `FastBufferWriter` and Reader IsInitialized property. (#1859)

### Changed

- Updated `UnityTransport` dependency on `com.unity.transport` to 1.0.0 (#1849)

### Removed

- Removed `SnapshotSystem` (#1852)
- Removed `com.unity.modules.animation`, `com.unity.modules.physics` and `com.unity.modules.physics2d` dependencies from the package (#1812)
- Removed `com.unity.collections` dependency from the package (#1849)

### Fixed
- Fixed in-scene placed NetworkObjects not being found/ignored after a client disconnects and then reconnects. (#1850)
- Fixed issue where `UnityTransport` send queues were not flushed when calling `DisconnectLocalClient` or `DisconnectRemoteClient`. (#1847)
- Fixed NetworkBehaviour dependency verification check for an existing NetworkObject not searching from root parent transform relative GameObject. (#1841)
- Fixed issue where entries were not being removed from the NetworkSpawnManager.OwnershipToObjectsTable. (#1838)
- Fixed ClientRpcs would always send to all connected clients by default as opposed to only sending to the NetworkObject's Observers list by default. (#1836)
- Fixed clarity for NetworkSceneManager client side notification when it receives a scene hash value that does not exist in its local hash table. (#1828)
- Fixed client throws a key not found exception when it times out using UNet or UTP. (#1821)
- Fixed network variable updates are no longer limited to 32,768 bytes when NetworkConfig.EnsureNetworkVariableLengthSafety is enabled. The limits are now determined by what the transport can send in a message. (#1811)
- Fixed in-scene NetworkObjects get destroyed if a client fails to connect and shuts down the NetworkManager. (#1809)
- Fixed user never being notified in the editor that a NetworkBehaviour requires a NetworkObject to function properly. (#1808)
- Fixed PlayerObjects and dynamically spawned NetworkObjects not being added to the NetworkClient's OwnedObjects (#1801)
- Fixed issue where NetworkManager would continue starting even if the NetworkTransport selected failed. (#1780)
- Fixed issue when spawning new player if an already existing player exists it does not remove IsPlayer from the previous player (#1779)
- Fixed lack of notification that NetworkManager and NetworkObject cannot be added to the same GameObject with in-editor notifications (#1777)
- Fixed parenting warning printing for false positives (#1855)

CHANGELOG.md

@@ -6,6 +6,43 @@ 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).
 
+## [1.0.0-pre.7] - 2022-04-01
+
+### Added
+
+- Added editor only check prior to entering into play mode if the currently open and active scene is in the build list and if not displays a dialog box asking the user if they would like to automatically add it prior to entering into play mode. (#1828)
+- Added `UnityTransport` implementation and `com.unity.transport` package dependency (#1823)
+- Added `NetworkVariableWritePermission` to `NetworkVariableBase` and implemented `Owner` client writable netvars. (#1762)
+- `UnityTransport` settings can now be set programmatically. (#1845)
+- `FastBufferWriter` and Reader IsInitialized property. (#1859)
+
+### Changed
+
+- Updated `UnityTransport` dependency on `com.unity.transport` to 1.0.0 (#1849)
+
+### Removed
+
+- Removed `SnapshotSystem` (#1852)
+- Removed `com.unity.modules.animation`, `com.unity.modules.physics` and `com.unity.modules.physics2d` dependencies from the package (#1812)
+- Removed `com.unity.collections` dependency from the package (#1849)
+
+### Fixed
+- Fixed in-scene placed NetworkObjects not being found/ignored after a client disconnects and then reconnects. (#1850)
+- Fixed issue where `UnityTransport` send queues were not flushed when calling `DisconnectLocalClient` or `DisconnectRemoteClient`. (#1847)
+- Fixed NetworkBehaviour dependency verification check for an existing NetworkObject not searching from root parent transform relative GameObject. (#1841)
+- Fixed issue where entries were not being removed from the NetworkSpawnManager.OwnershipToObjectsTable. (#1838)
+- Fixed ClientRpcs would always send to all connected clients by default as opposed to only sending to the NetworkObject's Observers list by default. (#1836)
+- Fixed clarity for NetworkSceneManager client side notification when it receives a scene hash value that does not exist in its local hash table. (#1828)
+- Fixed client throws a key not found exception when it times out using UNet or UTP. (#1821)
+- Fixed network variable updates are no longer limited to 32,768 bytes when NetworkConfig.EnsureNetworkVariableLengthSafety is enabled. The limits are now determined by what the transport can send in a message. (#1811)
+- Fixed in-scene NetworkObjects get destroyed if a client fails to connect and shuts down the NetworkManager. (#1809)
+- Fixed user never being notified in the editor that a NetworkBehaviour requires a NetworkObject to function properly. (#1808)
+- Fixed PlayerObjects and dynamically spawned NetworkObjects not being added to the NetworkClient's OwnedObjects (#1801)
+- Fixed issue where NetworkManager would continue starting even if the NetworkTransport selected failed. (#1780)
+- Fixed issue when spawning new player if an already existing player exists it does not remove IsPlayer from the previous player (#1779)
+- Fixed lack of notification that NetworkManager and NetworkObject cannot be added to the same GameObject with in-editor notifications (#1777)
+- Fixed parenting warning printing for false positives (#1855)
+
 ## [1.0.0-pre.6] - 2022-03-02
 
 ### Added
@@ -33,6 +70,7 @@ Additional documentation and release notes are available at [Multiplayer Documen
 - Fixed OwnedObjects not being properly modified when using ChangeOwnership (#1731)
 - Improved performance in NetworkAnimator (#1735)
 - Removed the "always sync" network animator (aka "autosend") parameters (#1746)
+- Fixed in-scene placed NetworkObjects not respawning after shutting down the NetworkManager and then starting it back up again (#1769)
 
 ## [1.0.0-pre.5] - 2022-01-26
 

Components/Interpolator/BufferedLinearInterpolator.cs

@@ -186,7 +186,14 @@ namespace Unity.Netcode
 
                     if (t < 0.0f)
                     {
-                        throw new OverflowException($"t = {t} but must be >= 0. range {range}, RenderTime {renderTime}, Start time {m_StartTimeConsumed}, end time {m_EndTimeConsumed}");
+                        // There is no mechanism to guarantee renderTime to not be before m_StartTimeConsumed
+                        // This clamps t to a minimum of 0 and fixes issues with longer frames and pauses
+
+                        if (NetworkLog.CurrentLogLevel <= LogLevel.Developer)
+                        {
+                            NetworkLog.LogError($"renderTime was before m_StartTimeConsumed. This should never happen. {nameof(renderTime)} is {renderTime}, {nameof(m_StartTimeConsumed)} is {m_StartTimeConsumed}");
+                        }
+                        t = 0.0f;
                     }
 
                     if (t > 3.0f) // max extrapolation
@@ -218,6 +225,8 @@ namespace Unity.Netcode
                 {
                     m_LastBufferedItemReceived = new BufferedItem(newMeasurement, sentTime);
                     ResetTo(newMeasurement, sentTime);
+                    // Next line keeps renderTime above m_StartTimeConsumed. Fixes pause/unpause issues
+                    m_Buffer.Add(m_LastBufferedItemReceived);
                 }
 
                 return;

Components/NetworkAnimator.cs

@@ -1,3 +1,4 @@
+#if COM_UNITY_MODULES_ANIMATION
 using Unity.Collections;
 using Unity.Collections.LowLevel.Unsafe;
 using UnityEngine;
@@ -5,7 +6,7 @@ using UnityEngine;
 namespace Unity.Netcode.Components
 {
     /// <summary>
-    /// A prototype component for syncing animations
+    /// NetworkAnimator enables remote synchronization of <see cref="UnityEngine.Animator"/> state for on network objects.
     /// </summary>
     [AddComponentMenu("Netcode/" + nameof(NetworkAnimator))]
     [RequireComponent(typeof(Animator))]
@@ -380,9 +381,7 @@ namespace Unity.Netcode.Components
             SetTrigger(Animator.StringToHash(triggerName));
         }
 
-        /// <summary>
-        /// Sets the trigger for the associated animation.  See note for SetTrigger(string)
-        /// </summary>
+        /// <inheritdoc cref="SetTrigger(string)" />
         /// <param name="hash">The hash for the trigger to activate</param>
         /// <param name="reset">If true, resets the trigger</param>
         public void SetTrigger(int hash, bool reset = false)
@@ -413,7 +412,7 @@ namespace Unity.Netcode.Components
         }
 
         /// <summary>
-        /// Resets the trigger for the associated animation.  See note for SetTrigger(string)
+        /// Resets the trigger for the associated animation.  See <see cref="SetTrigger(string)">SetTrigger</see> for more on how triggers are special
         /// </summary>
         /// <param name="triggerName">The string name of the trigger to reset</param>
         public void ResetTrigger(string triggerName)
@@ -421,13 +420,12 @@ namespace Unity.Netcode.Components
             ResetTrigger(Animator.StringToHash(triggerName));
         }
 
-        /// <summary>
-        /// Resets the trigger for the associated animation.  See note for SetTrigger(string)
-        /// </summary>
-        /// <param name="hash">The hash for the trigger to reset</param>
+        /// <inheritdoc cref="ResetTrigger(string)" path="summary" />
+        /// <param name="hash">The hash for the trigger to activate</param>
         public void ResetTrigger(int hash)
         {
             SetTrigger(hash, true);
         }
     }
 }
+#endif // COM_UNITY_MODULES_ANIMATION

Components/NetworkRigidbody.cs

@@ -1,3 +1,4 @@
+#if COM_UNITY_MODULES_PHYSICS
 using UnityEngine;
 
 namespace Unity.Netcode.Components
@@ -78,3 +79,4 @@ namespace Unity.Netcode.Components
         }
     }
 }
+#endif // COM_UNITY_MODULES_PHYSICS

Components/NetworkRigidbody2D.cs

@@ -1,3 +1,4 @@
+#if COM_UNITY_MODULES_PHYSICS2D
 using UnityEngine;
 
 namespace Unity.Netcode.Components
@@ -78,3 +79,4 @@ namespace Unity.Netcode.Components
         }
     }
 }
+#endif // COM_UNITY_MODULES_PHYSICS2D

Components/NetworkTransform.cs

@@ -272,7 +272,7 @@ namespace Unity.Netcode.Components
         /// If using different values, please use RPCs to write to the server. Netcode doesn't support client side network variable writing
         /// </summary>
         // This is public to make sure that users don't depend on this IsClient && IsOwner check in their code. If this logic changes in the future, we can make it invisible here
-        public bool CanCommitToTransform;
+        public bool CanCommitToTransform { get; protected set; }
         protected bool m_CachedIsServer;
         protected NetworkManager m_CachedNetworkManager;
 
@@ -691,7 +691,6 @@ namespace Unity.Netcode.Components
         {
             if (!NetworkObject.IsSpawned)
             {
-                // todo MTT-849 should never happen but yet it does! maybe revisit/dig after NetVar updates and snapshot system lands?
                 return;
             }
 
@@ -785,7 +784,7 @@ namespace Unity.Netcode.Components
             {
                 m_ReplicatedNetworkState.SetDirty(true);
             }
-            else
+            else if (m_Transform != null)
             {
                 ApplyInterpolatedNetworkStateToTransform(m_ReplicatedNetworkState.Value, m_Transform);
             }

Components/com.unity.netcode.components.asmdef

@@ -5,5 +5,22 @@
         "Unity.Netcode.Runtime",
         "Unity.Collections"
     ],
-    "allowUnsafeCode": true
+    "allowUnsafeCode": true,
+    "versionDefines": [
+        {
+            "name": "com.unity.modules.animation",
+            "expression": "",
+            "define": "COM_UNITY_MODULES_ANIMATION"
+        },
+        {
+            "name": "com.unity.modules.physics",
+            "expression": "",
+            "define": "COM_UNITY_MODULES_PHYSICS"
+        },
+        {
+            "name": "com.unity.modules.physics2d",
+            "expression": "",
+            "define": "COM_UNITY_MODULES_PHYSICS2D"
+        }
+    ]
 }

Editor/NetworkAnimatorEditor.cs

@@ -1,23 +0,0 @@
-using Unity.Netcode.Components;
-using UnityEditor;
-using UnityEngine;
-
-namespace Unity.Netcode.Editor
-{
-    [CustomEditor(typeof(NetworkAnimator), true)]
-    [CanEditMultipleObjects]
-    public class NetworkAnimatorEditor : UnityEditor.Editor
-    {
-        public override void OnInspectorGUI()
-        {
-            serializedObject.Update();
-
-            EditorGUI.BeginChangeCheck();
-            var label = new GUIContent("Animator", "The Animator component to synchronize");
-            EditorGUILayout.PropertyField(serializedObject.FindProperty("m_Animator"), label);
-            EditorGUI.EndChangeCheck();
-
-            serializedObject.ApplyModifiedProperties();
-        }
-    }
-}

Editor/NetworkBehaviourEditor.cs

@@ -211,5 +211,91 @@ namespace Unity.Netcode.Editor
             serializedObject.ApplyModifiedProperties();
             EditorGUI.EndChangeCheck();
         }
+
+        /// <summary>
+        /// Invoked once when a NetworkBehaviour component is
+        /// displayed in the inspector view.
+        /// </summary>
+        private void OnEnable()
+        {
+            // When we first add a NetworkBehaviour this editor will be enabled
+            // so we go ahead and check for an already existing NetworkObject here
+            CheckForNetworkObject((target as NetworkBehaviour).gameObject);
+        }
+
+        internal const string AutoAddNetworkObjectIfNoneExists = "AutoAdd-NetworkObject-When-None-Exist";
+
+        public static Transform GetRootParentTransform(Transform transform)
+        {
+            if (transform.parent == null || transform.parent == transform)
+            {
+                return transform;
+            }
+            return GetRootParentTransform(transform.parent);
+        }
+
+        /// <summary>
+        /// Used to determine if a GameObject has one or more NetworkBehaviours but
+        /// does not already have a NetworkObject component.  If not it will notify
+        /// the user that NetworkBehaviours require a NetworkObject.
+        /// </summary>
+        public static void CheckForNetworkObject(GameObject gameObject, bool networkObjectRemoved = false)
+        {
+            // If there are no NetworkBehaviours or no gameObject, then exit early
+            if (gameObject == null || (gameObject.GetComponent<NetworkBehaviour>() == null && gameObject.GetComponentInChildren<NetworkBehaviour>() == null))
+            {
+                return;
+            }
+
+            // Now get the root parent transform to the current GameObject (or itself)
+            var rootTransform = GetRootParentTransform(gameObject.transform);
+
+            // Otherwise, check to see if there is any NetworkObject from the root GameObject down to all children.
+            // If not, notify the user that NetworkBehaviours require that the relative GameObject has a NetworkObject component.
+            var networkObject = rootTransform.GetComponent<NetworkObject>();
+            if (networkObject == null)
+            {
+                networkObject = rootTransform.GetComponentInChildren<NetworkObject>();
+
+                if (networkObject == null)
+                {
+                    // If we are removing a NetworkObject but there is still one or more NetworkBehaviour components
+                    // and the user has already turned "Auto-Add NetworkObject" on when first notified about the requirement
+                    // then just send a reminder to the user why the NetworkObject they just deleted seemingly "re-appeared"
+                    // again.
+                    if (networkObjectRemoved && EditorPrefs.HasKey(AutoAddNetworkObjectIfNoneExists) && EditorPrefs.GetBool(AutoAddNetworkObjectIfNoneExists))
+                    {
+                        Debug.LogWarning($"{gameObject.name} still has {nameof(NetworkBehaviour)}s and Auto-Add NetworkObjects is enabled. A NetworkObject is being added back to {gameObject.name}.");
+                        Debug.Log($"To reset Auto-Add NetworkObjects: Select the Netcode->General->Reset Auto-Add NetworkObject menu item.");
+                    }
+
+                    // Notify and provide the option to add it one time, always add a NetworkObject, or do nothing and let the user manually add it
+                    if (EditorUtility.DisplayDialog($"{nameof(NetworkBehaviour)}s require a {nameof(NetworkObject)}",
+                    $"{gameObject.name} does not have a {nameof(NetworkObject)} component.  Would you like to add one now?", "Yes", "No (manually add it)",
+                    DialogOptOutDecisionType.ForThisMachine, AutoAddNetworkObjectIfNoneExists))
+                    {
+                        gameObject.AddComponent<NetworkObject>();
+                        var activeScene = UnityEngine.SceneManagement.SceneManager.GetActiveScene();
+                        UnityEditor.SceneManagement.EditorSceneManager.MarkSceneDirty(activeScene);
+                        UnityEditor.SceneManagement.EditorSceneManager.SaveScene(activeScene);
+                    }
+                }
+            }
+        }
+
+        /// <summary>
+        /// This allows users to reset the Auto-Add NetworkObject preference
+        /// so the next time they add a NetworkBehaviour to a GameObject without
+        /// a NetworkObject it will display the dialog box again and not
+        /// automatically add a NetworkObject.
+        /// </summary>
+        [MenuItem("Netcode/General/Reset Auto-Add NetworkObject", false, 1)]
+        private static void ResetMultiplayerToolsTipStatus()
+        {
+            if (EditorPrefs.HasKey(AutoAddNetworkObjectIfNoneExists))
+            {
+                EditorPrefs.SetBool(AutoAddNetworkObjectIfNoneExists, false);
+            }
+        }
     }
 }

Editor/NetworkManagerEditor.cs

@@ -134,10 +134,14 @@ namespace Unity.Netcode.Editor
         {
             m_NetworkPrefabsList = new ReorderableList(serializedObject, serializedObject.FindProperty(nameof(NetworkManager.NetworkConfig)).FindPropertyRelative(nameof(NetworkConfig.NetworkPrefabs)), true, true, true, true);
             m_NetworkPrefabsList.elementHeightCallback = index =>
+            {
+                var networkOverrideInt = 0;
+                if (m_NetworkPrefabsList.count > 0)
                 {
                     var networkPrefab = m_NetworkPrefabsList.serializedProperty.GetArrayElementAtIndex(index);
                     var networkOverrideProp = networkPrefab.FindPropertyRelative(nameof(NetworkPrefab.Override));
-                var networkOverrideInt = networkOverrideProp.enumValueIndex;
+                    networkOverrideInt = networkOverrideProp.enumValueIndex;
+                }
 
                 return 8 + (networkOverrideInt == 0 ? EditorGUIUtility.singleLineHeight : (EditorGUIUtility.singleLineHeight * 2) + 5);
             };

Editor/NetworkManagerHelper.cs

@@ -1,5 +1,7 @@
 using System.Collections.Generic;
+using System.Linq;
 using UnityEngine;
+using UnityEngine.SceneManagement;
 using UnityEditor;
 
 namespace Unity.Netcode.Editor
@@ -25,7 +27,6 @@ namespace Unity.Netcode.Editor
         {
             Singleton = new NetworkManagerHelper();
             NetworkManager.NetworkManagerHelper = Singleton;
-
             EditorApplication.playModeStateChanged -= EditorApplication_playModeStateChanged;
             EditorApplication.hierarchyChanged -= EditorApplication_hierarchyChanged;
 
@@ -40,19 +41,105 @@ namespace Unity.Netcode.Editor
                 case PlayModeStateChange.ExitingEditMode:
                     {
                         s_LastKnownNetworkManagerParents.Clear();
+                        ScenesInBuildActiveSceneCheck();
                         break;
                     }
             }
         }
 
+        /// <summary>
+        /// Detects if a user is trying to enter into play mode when both conditions are true:
+        /// - the currently active and open scene is not added to the scenes in build list
+        /// - an instance of a NetworkManager with scene management enabled can be found
+        /// If both conditions are met then the user is presented with a dialog box that
+        /// provides the user with the option to add the scene to the scenes in build list
+        /// before entering into play mode or the user can continue under those conditions.
+        ///
+        /// ** When scene management is enabled the user should treat all scenes that need to
+        /// be synchronized using network scene management as if they were preparing for a build.
+        /// Any scene that needs to be loaded at run time has to be included in the scenes in
+        /// build list. **
+        /// </summary>
+        private static void ScenesInBuildActiveSceneCheck()
+        {
+            var scenesList = EditorBuildSettings.scenes.ToList();
+            var activeScene = SceneManager.GetActiveScene();
+            var isSceneInBuildSettings = scenesList.Where((c) => c.path == activeScene.path).Count() == 1;
+            var networkManager = Object.FindObjectOfType<NetworkManager>();
+            if (!isSceneInBuildSettings && networkManager != null)
+            {
+                if (networkManager.NetworkConfig != null && networkManager.NetworkConfig.EnableSceneManagement)
+                {
+                    if (EditorUtility.DisplayDialog("Add Scene to Scenes in Build", $"The current scene was not found in the scenes" +
+                        $" in build and a {nameof(NetworkManager)} instance was found with scene management enabled! Clients will not be able " +
+                        $"to synchronize to this scene unless it is added to the scenes in build list.\n\nWould you like to add it now?",
+                        "Yes", "No - Continue"))
+                    {
+                        scenesList.Add(new EditorBuildSettingsScene(activeScene.path, true));
+                        EditorBuildSettings.scenes = scenesList.ToArray();
+                    }
+                }
+            }
+        }
+
+        /// <summary>
+        /// Invoked only when the hierarchy changes
+        /// </summary>
         private static void EditorApplication_hierarchyChanged()
         {
             var allNetworkManagers = Resources.FindObjectsOfTypeAll<NetworkManager>();
             foreach (var networkManager in allNetworkManagers)
             {
-                networkManager.NetworkManagerCheckForParent();
+                if (!networkManager.NetworkManagerCheckForParent())
+                {
+                    Singleton.CheckAndNotifyUserNetworkObjectRemoved(networkManager);
                 }
             }
+        }
+
+        /// <summary>
+        /// Handles notifying users that they cannot add a NetworkObject component
+        /// to a GameObject that also has a NetworkManager component. The NetworkObject
+        /// will always be removed.
+        /// GameObject + NetworkObject then NetworkManager = NetworkObject removed
+        /// GameObject + NetworkManager then NetworkObject = NetworkObject removed
+        /// Note: Since this is always invoked after <see cref="NetworkManagerCheckForParent"/>
+        /// we do not need to check for parent when searching for a NetworkObject component
+        /// </summary>
+        public void CheckAndNotifyUserNetworkObjectRemoved(NetworkManager networkManager, bool editorTest = false)
+        {
+            // Check for any NetworkObject at the same gameObject relative layer
+            var networkObject = networkManager.gameObject.GetComponent<NetworkObject>();
+
+            if (networkObject == null)
+            {
+                // if none is found, check to see if any children have a NetworkObject
+                networkObject = networkManager.gameObject.GetComponentInChildren<NetworkObject>();
+                if (networkObject == null)
+                {
+                    return;
+                }
+            }
+
+            if (!EditorApplication.isUpdating)
+            {
+                Object.DestroyImmediate(networkObject);
+
+                if (!EditorApplication.isPlaying && !editorTest)
+                {
+                    EditorUtility.DisplayDialog($"Removing {nameof(NetworkObject)}", NetworkManagerAndNetworkObjectNotAllowedMessage(), "OK");
+                }
+                else
+                {
+                    Debug.LogError(NetworkManagerAndNetworkObjectNotAllowedMessage());
+                }
+            }
+        }
+
+        public string NetworkManagerAndNetworkObjectNotAllowedMessage()
+        {
+            return $"A {nameof(GameObject)} cannot have both a {nameof(NetworkManager)} and {nameof(NetworkObject)} assigned to it or any children under it.";
+        }
 
         /// <summary>
         /// Handles notifying the user, via display dialog window, that they have nested a NetworkManager.

Editor/NetworkObjectEditor.cs

@@ -100,5 +100,32 @@ namespace Unity.Netcode.Editor
                 GUI.enabled = guiEnabled;
             }
         }
+
+        // Saved for use in OnDestroy
+        private GameObject m_GameObject;
+
+        /// <summary>
+        /// Invoked once when a NetworkObject component is
+        /// displayed in the inspector view.
+        /// </summary>
+        private void OnEnable()
+        {
+            // We set the GameObject upon being enabled because when the
+            // NetworkObject component is removed (i.e. when OnDestroy is invoked)
+            // it is no longer valid/available.
+            m_GameObject = (target as NetworkObject).gameObject;
+        }
+
+        /// <summary>
+        /// Invoked once when a NetworkObject component is
+        /// no longer displayed in the inspector view.
+        /// </summary>
+        private void OnDestroy()
+        {
+            // Since this is also invoked when a NetworkObject component is removed
+            // from a GameObject, we go ahead and check for a NetworkObject when
+            // this custom editor is destroyed.
+            NetworkBehaviourEditor.CheckForNetworkObject(m_GameObject, true);
+        }
     }
 }

Editor/NetworkTransformEditor.cs

@@ -4,7 +4,7 @@ using Unity.Netcode.Components;
 
 namespace Unity.Netcode.Editor
 {
-    [CustomEditor(typeof(NetworkTransform))]
+    [CustomEditor(typeof(NetworkTransform), true)]
     public class NetworkTransformEditor : UnityEditor.Editor
     {
         private SerializedProperty m_SyncPositionXProperty;
@@ -112,6 +112,7 @@ namespace Unity.Netcode.Editor
             EditorGUILayout.PropertyField(m_InLocalSpaceProperty);
             EditorGUILayout.PropertyField(m_InterpolateProperty);
 
+#if COM_UNITY_MODULES_PHYSICS
             // if rigidbody is present but network rigidbody is not present
             var go = ((NetworkTransform)target).gameObject;
             if (go.TryGetComponent<Rigidbody>(out _) && go.TryGetComponent<NetworkRigidbody>(out _) == false)
@@ -119,12 +120,15 @@ namespace Unity.Netcode.Editor
                 EditorGUILayout.HelpBox("This GameObject contains a Rigidbody but no NetworkRigidbody.\n" +
                     "Add a NetworkRigidbody component to improve Rigidbody synchronization.", MessageType.Warning);
             }
+#endif // COM_UNITY_MODULES_PHYSICS
 
+#if COM_UNITY_MODULES_PHYSICS2D
             if (go.TryGetComponent<Rigidbody2D>(out _) && go.TryGetComponent<NetworkRigidbody2D>(out _) == false)
             {
                 EditorGUILayout.HelpBox("This GameObject contains a Rigidbody2D but no NetworkRigidbody2D.\n" +
                     "Add a NetworkRigidbody2D component to improve Rigidbody2D synchronization.", MessageType.Warning);
             }
+#endif // COM_UNITY_MODULES_PHYSICS2D
 
             serializedObject.ApplyModifiedProperties();
         }

Editor/PackageChecker.meta

@@ -0,0 +1,8 @@
+fileFormatVersion: 2
+guid: a325130169714440ba1b4878082e8956
+folderAsset: yes
+DefaultImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Editor/PackageChecker/UTPAdapterChecker.cs

@@ -0,0 +1,53 @@
+#if COM_UNITY_NETCODE_ADAPTER_UTP
+using System.Linq;
+using UnityEngine;
+using UnityEditor;
+using UnityEditor.PackageManager;
+using UnityEditor.PackageManager.Requests;
+
+namespace Unity.Netcode.Editor.PackageChecker
+{
+    [InitializeOnLoad]
+    internal class UTPAdapterChecker
+    {
+        private const string k_UTPAdapterPackageName = "com.unity.netcode.adapter.utp";
+
+        private static ListRequest s_ListRequest = null;
+
+        static UTPAdapterChecker()
+        {
+            if (s_ListRequest == null)
+            {
+                s_ListRequest = Client.List();
+                EditorApplication.update += EditorUpdate;
+            }
+        }
+
+        private static void EditorUpdate()
+        {
+            if (!s_ListRequest.IsCompleted)
+            {
+                return;
+            }
+
+            EditorApplication.update -= EditorUpdate;
+
+            if (s_ListRequest.Status == StatusCode.Success)
+            {
+                if (s_ListRequest.Result.Any(p => p.name == k_UTPAdapterPackageName))
+                {
+                    Debug.Log($"({nameof(UTPAdapterChecker)}) Found UTP Adapter package, it is no longer needed, `UnityTransport` is now directly integrated into the SDK therefore removing it from the project.");
+                    Client.Remove(k_UTPAdapterPackageName);
+                }
+            }
+            else
+            {
+                var error = s_ListRequest.Error;
+                Debug.LogError($"({nameof(UTPAdapterChecker)}) Cannot check the list of packages -> error #{error.errorCode}: {error.message}");
+            }
+
+            s_ListRequest = null;
+        }
+    }
+}
+#endif // COM_UNITY_NETCODE_ADAPTER_UTP

Editor/PackageChecker/UTPAdapterChecker.cs.meta

@@ -1,5 +1,5 @@
 fileFormatVersion: 2
-guid: 69c3c1c5a885d4aed99ee2e1fa40f763
+guid: df5ed97df956b4aad91a221ba59fa304
 MonoImporter:
   externalObjects: {}
   serializedVersion: 2

Editor/PackageChecker/com.unity.netcode.editor.packagechecker.asmdef

@@ -0,0 +1,14 @@
+{
+    "name": "Unity.Netcode.Editor.PackageChecker",
+    "rootNamespace": "Unity.Netcode.Editor.PackageChecker",
+    "includePlatforms": [
+        "Editor"
+    ],
+    "versionDefines": [
+        {
+            "name": "com.unity.netcode.adapter.utp",
+            "expression": "",
+            "define": "COM_UNITY_NETCODE_ADAPTER_UTP"
+        }
+    ]
+}

Editor/PackageChecker/com.unity.netcode.editor.packagechecker.asmdef.meta

@@ -0,0 +1,7 @@
+fileFormatVersion: 2
+guid: de64d7f9ca85d4bf59c8c24738bc1057
+AssemblyDefinitionImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Runtime/AssemblyInfo.cs

@@ -11,4 +11,3 @@ using System.Runtime.CompilerServices;
 [assembly: InternalsVisibleTo("Unity.Netcode.RuntimeTests")]
 [assembly: InternalsVisibleTo("Unity.Netcode.TestHelpers.Runtime")]
 [assembly: InternalsVisibleTo("Unity.Netcode.Adapter.UTP")]
-

Runtime/Configuration/NetworkConfig.cs

@@ -138,19 +138,6 @@ namespace Unity.Netcode
         /// </summary>
         public bool EnableNetworkLogs = true;
 
-        /// <summary>
-        /// Whether or not to enable Snapshot System for variable updates. Not supported in this version.
-        /// </summary>
-        public bool UseSnapshotDelta { get; internal set; } = false;
-        /// <summary>
-        /// Whether or not to enable Snapshot System for spawn and despawn commands. Not supported in this version.
-        /// </summary>
-        public bool UseSnapshotSpawn { get; internal set; } = false;
-        /// <summary>
-        /// When Snapshot System spawn is enabled: max size of Snapshot Messages. Meant to fit MTU.
-        /// </summary>
-        public int SnapshotMaxSpawnUsage { get; } = 1000;
-
         public const int RttAverageSamples = 5; // number of RTT to keep an average of (plus one)
         public const int RttWindowSize = 64; // number of slots to use for RTT computations (max number of in-flight packets)
         /// <summary>

Runtime/Connection/NetworkClient.cs

@@ -20,6 +20,17 @@ namespace Unity.Netcode
         /// <summary>
         /// The NetworkObject's owned by this Client
         /// </summary>
-        public readonly List<NetworkObject> OwnedObjects = new List<NetworkObject>();
+        public List<NetworkObject> OwnedObjects
+        {
+            get
+            {
+                if (PlayerObject != null && PlayerObject.NetworkManager != null && PlayerObject.NetworkManager.IsListening)
+                {
+                    return PlayerObject.NetworkManager.SpawnManager.GetClientOwnedObjects(ClientId);
+                }
+
+                return new List<NetworkObject>();
+            }
+        }
     }
 }

Runtime/Core/IndexAllocator.cs

@@ -1,388 +0,0 @@
-using UnityEngine;
-
-namespace Unity.Netcode
-{
-    internal struct IndexAllocatorEntry
-    {
-        internal int Pos; // Position where the memory of this slot is
-        internal int Length; // Length of the memory allocated to this slot
-        internal int Next; // Next and Prev define the order of the slots in the buffer
-        internal int Prev;
-        internal bool Free;  // Whether this is a free slot
-    }
-
-    internal class IndexAllocator
-    {
-        private const int k_NotSet = -1;
-        private readonly int m_MaxSlot; // Maximum number of sections (free or not) in the buffer
-        private readonly int m_BufferSize; // Size of the buffer we allocated into
-        private int m_LastSlot = 0; // Last allocated slot
-        private IndexAllocatorEntry[] m_Slots; // Array of slots
-        private int[] m_IndexToSlot; // Mapping from the client's index to the slot index
-
-        internal IndexAllocator(int bufferSize, int maxSlot)
-        {
-            m_MaxSlot = maxSlot;
-            m_BufferSize = bufferSize;
-            m_Slots = new IndexAllocatorEntry[m_MaxSlot];
-            m_IndexToSlot = new int[m_MaxSlot];
-            Reset();
-        }
-
-        /// <summary>
-        /// Reset this IndexAllocator to an empty one, with the same sized buffer and slots
-        /// </summary>
-        internal void Reset()
-        {
-            // todo: could be made faster, for example by having a last index
-            // and not needing valid stuff past it
-            for (int i = 0; i < m_MaxSlot; i++)
-            {
-                m_Slots[i].Free = true;
-                m_Slots[i].Next = i + 1;
-                m_Slots[i].Prev = i - 1;
-                m_Slots[i].Pos = m_BufferSize;
-                m_Slots[i].Length = 0;
-
-                m_IndexToSlot[i] = k_NotSet;
-            }
-
-            m_Slots[0].Pos = 0;
-            m_Slots[0].Length = m_BufferSize;
-            m_Slots[0].Prev = k_NotSet;
-            m_Slots[m_MaxSlot - 1].Next = k_NotSet;
-        }
-
-        /// <summary>
-        /// Returns the amount of memory used
-        /// </summary>
-        /// <returns>
-        /// Returns the amount of memory used, starting at 0, ending after the last used slot
-        /// </returns>
-        internal int Range
-        {
-            get
-            {
-                // when the whole buffer is free, m_LastSlot points to an empty slot
-                if (m_Slots[m_LastSlot].Free)
-                {
-                    return 0;
-                }
-                // otherwise return the end of the last slot used
-                return m_Slots[m_LastSlot].Pos + m_Slots[m_LastSlot].Length;
-            }
-        }
-
-        /// <summary>
-        /// Allocate a slot with "size" position, for index "index"
-        /// </summary>
-        /// <param name="index">The client index to identify this. Used in Deallocate to identify which slot</param>
-        /// <param name="size">The size required. </param>
-        /// <param name="pos">Returns the position to use in the buffer </param>
-        /// <returns>
-        /// true if successful, false is there isn't enough memory available or no slots are large enough
-        /// </returns>
-        internal bool Allocate(int index, int size, out int pos)
-        {
-            pos = 0;
-            // size must be positive, index must be within range
-            if (size < 0 || index < 0 || index >= m_MaxSlot)
-            {
-                return false;
-            }
-
-            // refuse allocation if the index is already in use
-            if (m_IndexToSlot[index] != k_NotSet)
-            {
-                return false;
-            }
-
-            // todo: this is the slowest part
-            // improvement 1: list of free blocks (minor)
-            // improvement 2: heap of free blocks
-            for (int i = 0; i < m_MaxSlot; i++)
-            {
-                if (m_Slots[i].Free && m_Slots[i].Length >= size)
-                {
-                    m_IndexToSlot[index] = i;
-
-                    int leftOver = m_Slots[i].Length - size;
-                    int next = m_Slots[i].Next;
-                    if (m_Slots[next].Free)
-                    {
-                        m_Slots[next].Pos -= leftOver;
-                        m_Slots[next].Length += leftOver;
-                    }
-                    else
-                    {
-                        int add = MoveSlotAfter(i);
-
-                        m_Slots[add].Pos = m_Slots[i].Pos + size;
-                        m_Slots[add].Length = m_Slots[i].Length - size;
-                    }
-
-                    m_Slots[i].Free = false;
-                    m_Slots[i].Length = size;
-
-                    pos = m_Slots[i].Pos;
-
-                    // if we allocate past the current range, we are the last slot
-                    if (m_Slots[i].Pos + m_Slots[i].Length > Range)
-                    {
-                        m_LastSlot = i;
-                    }
-
-                    return true;
-                }
-            }
-
-            return false;
-        }
-
-        /// <summary>
-        /// Deallocate a slot
-        /// </summary>
-        /// <param name="index">The client index to identify this. Same index used in Allocate </param>
-        /// <returns>
-        /// true if successful, false is there isn't an allocated slot at this index
-        /// </returns>
-        internal bool Deallocate(int index)
-        {
-            // size must be positive, index must be within range
-            if (index < 0 || index >= m_MaxSlot)
-            {
-                return false;
-            }
-
-            int slot = m_IndexToSlot[index];
-
-            if (slot == k_NotSet)
-            {
-                return false;
-            }
-
-            if (m_Slots[slot].Free)
-            {
-                return false;
-            }
-
-            m_Slots[slot].Free = true;
-
-            int prev = m_Slots[slot].Prev;
-            int next = m_Slots[slot].Next;
-
-            // if previous slot was free, merge and grow
-            if (prev != k_NotSet && m_Slots[prev].Free)
-            {
-                m_Slots[prev].Length += m_Slots[slot].Length;
-                m_Slots[slot].Length = 0;
-
-                // if the slot we're merging was the last one, the last one is now the one we merged with
-                if (slot == m_LastSlot)
-                {
-                    m_LastSlot = prev;
-                }
-
-                // todo: verify what this does on full or nearly full cases
-                MoveSlotToEnd(slot);
-                slot = prev;
-            }
-
-            next = m_Slots[slot].Next;
-
-            // merge with next slot if it is free
-            if (next != k_NotSet && m_Slots[next].Free)
-            {
-                m_Slots[slot].Length += m_Slots[next].Length;
-                m_Slots[next].Length = 0;
-                MoveSlotToEnd(next);
-            }
-
-            // if we just deallocate the last one, we need to move last back
-            if (slot == m_LastSlot)
-            {
-                m_LastSlot = m_Slots[m_LastSlot].Prev;
-                // if there's nothing allocated anymore, use 0
-                if (m_LastSlot == k_NotSet)
-                {
-                    m_LastSlot = 0;
-                }
-            }
-
-            // mark the index as available
-            m_IndexToSlot[index] = k_NotSet;
-
-            return true;
-        }
-
-        // Take a slot at the end and link it to go just after "slot".
-        // Used when allocating part of a slot and we need an entry for the rest
-        // Returns the slot that was picked
-        private int MoveSlotAfter(int slot)
-        {
-            int ret = m_Slots[m_MaxSlot - 1].Prev;
-            int p0 = m_Slots[ret].Prev;
-
-            m_Slots[p0].Next = m_MaxSlot - 1;
-            m_Slots[m_MaxSlot - 1].Prev = p0;
-
-            int p1 = m_Slots[slot].Next;
-            m_Slots[slot].Next = ret;
-            m_Slots[p1].Prev = ret;
-
-            m_Slots[ret].Prev = slot;
-            m_Slots[ret].Next = p1;
-
-            return ret;
-        }
-
-        // Move the slot "slot" to the end of the list.
-        // Used when merging two slots, that gives us an extra entry at the end
-        private void MoveSlotToEnd(int slot)
-        {
-            // if we're already there
-            if (m_Slots[slot].Next == k_NotSet)
-            {
-                return;
-            }
-
-            int prev = m_Slots[slot].Prev;
-            int next = m_Slots[slot].Next;
-
-            m_Slots[prev].Next = next;
-            if (next != k_NotSet)
-            {
-                m_Slots[next].Prev = prev;
-            }
-
-            int p0 = m_Slots[m_MaxSlot - 1].Prev;
-
-            m_Slots[p0].Next = slot;
-            m_Slots[slot].Next = m_MaxSlot - 1;
-
-            m_Slots[m_MaxSlot - 1].Prev = slot;
-            m_Slots[slot].Prev = p0;
-
-            m_Slots[slot].Pos = m_BufferSize;
-        }
-
-        // runs a bunch of consistency check on the Allocator
-        internal bool Verify()
-        {
-            int pos = k_NotSet;
-            int count = 0;
-            int total = 0;
-            int endPos = 0;
-
-            do
-            {
-                int prev = pos;
-                if (pos != k_NotSet)
-                {
-                    pos = m_Slots[pos].Next;
-                    if (pos == k_NotSet)
-                    {
-                        break;
-                    }
-                }
-                else
-                {
-                    pos = 0;
-                }
-
-                if (m_Slots[pos].Prev != prev)
-                {
-                    // the previous is not correct
-                    return false;
-                }
-
-                if (m_Slots[pos].Length < 0)
-                {
-                    // Length should be positive
-                    return false;
-                }
-
-                if (prev != k_NotSet && m_Slots[prev].Free && m_Slots[pos].Free && m_Slots[pos].Length > 0)
-                {
-                    // should not have two consecutive free slots
-                    return false;
-                }
-
-                if (m_Slots[pos].Pos != total)
-                {
-                    // slots should all line up nicely
-                    return false;
-                }
-
-                if (!m_Slots[pos].Free)
-                {
-                    endPos = m_Slots[pos].Pos + m_Slots[pos].Length;
-                }
-
-                total += m_Slots[pos].Length;
-                count++;
-
-            } while (pos != k_NotSet);
-
-            if (count != m_MaxSlot)
-            {
-                // some slots were lost
-                return false;
-            }
-
-            if (total != m_BufferSize)
-            {
-                // total buffer should be accounted for
-                return false;
-            }
-
-            if (endPos != Range)
-            {
-                // end position should match reported end position
-                return false;
-            }
-
-            return true;
-        }
-
-        // Debug display the allocator structure
-        internal void DebugDisplay()
-        {
-            string logMessage = "IndexAllocator structure\n";
-
-            bool[] seen = new bool[m_MaxSlot];
-
-            int pos = 0;
-            int count = 0;
-            bool prevEmpty = false;
-            do
-            {
-                seen[pos] = true;
-                count++;
-                if (m_Slots[pos].Length == 0 && prevEmpty)
-                {
-                    // don't display repetitive empty slots
-                }
-                else
-                {
-                    logMessage += string.Format("{0}:{1}, {2} ({3}) \n", m_Slots[pos].Pos, m_Slots[pos].Length,
-                        m_Slots[pos].Free ? "Free" : "Used", pos);
-                    if (m_Slots[pos].Length == 0)
-                    {
-                        prevEmpty = true;
-                    }
-                    else
-                    {
-                        prevEmpty = false;
-                    }
-                }
-
-                pos = m_Slots[pos].Next;
-            } while (pos != k_NotSet && !seen[pos]);
-
-            logMessage += string.Format("{0} Total entries\n", count);
-
-            Debug.Log(logMessage);
-        }
-    }
-}

Runtime/Core/NetworkBehaviour.cs

@@ -158,37 +158,57 @@ 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;
-
             if (clientRpcParams.Send.TargetClientIds != null)
             {
-                foreach (var clientId in clientRpcParams.Send.TargetClientIds)
+                foreach (var targetClientId in clientRpcParams.Send.TargetClientIds)
                 {
-                    if (clientId == NetworkManager.ServerClientId)
+                    if (targetClientId == NetworkManager.ServerClientId)
                     {
                         shouldSendToHost = true;
                         break;
                     }
+
+                    // Check to make sure we are sending to only observers, if not log an error.
+                    if (NetworkManager.LogLevel >= LogLevel.Error && !NetworkObject.Observers.Contains(targetClientId))
+                    {
+                        NetworkLog.LogError(GenerateObserverErrorMessage(clientRpcParams, targetClientId));
+                    }
                 }
 
                 rpcWriteSize = NetworkManager.SendMessage(ref clientRpcMessage, networkDelivery, in clientRpcParams.Send.TargetClientIds);
             }
             else if (clientRpcParams.Send.TargetClientIdsNativeArray != null)
             {
-                foreach (var clientId in clientRpcParams.Send.TargetClientIdsNativeArray)
+                foreach (var targetClientId in clientRpcParams.Send.TargetClientIdsNativeArray)
                 {
-                    if (clientId == NetworkManager.ServerClientId)
+                    if (targetClientId == NetworkManager.ServerClientId)
                     {
                         shouldSendToHost = true;
                         break;
                     }
+
+                    // Check to make sure we are sending to only observers, if not log an error.
+                    if (NetworkManager.LogLevel >= LogLevel.Error && !NetworkObject.Observers.Contains(targetClientId))
+                    {
+                        NetworkLog.LogError(GenerateObserverErrorMessage(clientRpcParams, targetClientId));
+                    }
                 }
 
                 rpcWriteSize = NetworkManager.SendMessage(ref clientRpcMessage, networkDelivery, clientRpcParams.Send.TargetClientIdsNativeArray.Value);
             }
             else
             {
-                shouldSendToHost = IsHost;
-                rpcWriteSize = NetworkManager.SendMessage(ref clientRpcMessage, networkDelivery, NetworkManager.ConnectedClientsIds);
+                var observerEnumerator = NetworkObject.Observers.GetEnumerator();
+                while (observerEnumerator.MoveNext())
+                {
+                    // Skip over the host
+                    if (IsHost && observerEnumerator.Current == NetworkManager.LocalClientId)
+                    {
+                        shouldSendToHost = true;
+                        continue;
+                    }
+                    rpcWriteSize = NetworkManager.MessagingSystem.SendMessage(ref clientRpcMessage, networkDelivery, observerEnumerator.Current);
+                }
             }
 
             // If we are a server/host then we just no op and send to ourself
@@ -228,6 +248,12 @@ namespace Unity.Netcode
 #endif
         }
 
+        internal string GenerateObserverErrorMessage(ClientRpcParams clientRpcParams, ulong targetClientId)
+        {
+            var containerNameHoldingId = clientRpcParams.Send.TargetClientIds != null ? nameof(ClientRpcParams.Send.TargetClientIds) : nameof(ClientRpcParams.Send.TargetClientIdsNativeArray);
+            return $"Sending ClientRpc to non-observer! {containerNameHoldingId} contains clientId {targetClientId} that is not an observer!";
+        }
+
         /// <summary>
         /// Gets the NetworkManager that owns this NetworkBehaviour instance
         ///   See note around `NetworkObject` for how there is a chicken / egg problem when we are not initialized
@@ -235,42 +261,42 @@ namespace Unity.Netcode
         public NetworkManager NetworkManager => NetworkObject.NetworkManager;
 
         /// <summary>
-        /// Gets if the object is the the personal clients player object
+        /// 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.
         /// </summary>
-        public bool IsLocalPlayer => NetworkObject.IsLocalPlayer;
+        public bool IsLocalPlayer { get; private set; }
 
         /// <summary>
         /// Gets if the object is owned by the local player or if the object is the local player object
         /// </summary>
-        public bool IsOwner => NetworkObject.IsOwner;
+        public bool IsOwner { get; internal set; }
 
         /// <summary>
         /// Gets if we are executing as server
         /// </summary>
-        protected bool IsServer => IsRunning && NetworkManager.IsServer;
+        protected bool IsServer { get; private set; }
 
         /// <summary>
         /// Gets if we are executing as client
         /// </summary>
-        protected bool IsClient => IsRunning && NetworkManager.IsClient;
+        protected bool IsClient { get; private set; }
+
 
         /// <summary>
         /// Gets if we are executing as Host, I.E Server and Client
         /// </summary>
-        protected bool IsHost => IsRunning && NetworkManager.IsHost;
-
-        private bool IsRunning => NetworkManager && NetworkManager.IsListening;
+        protected bool IsHost { get; private set; }
 
         /// <summary>
         /// Gets Whether or not the object has a owner
         /// </summary>
-        public bool IsOwnedByServer => NetworkObject.IsOwnedByServer;
+        public bool IsOwnedByServer { get; internal set; }
 
         /// <summary>
         /// Used to determine if it is safe to access NetworkObject and NetworkManager from within a NetworkBehaviour component
         /// Primarily useful when checking NetworkObject/NetworkManager properties within FixedUpate
         /// </summary>
-        public bool IsSpawned => HasNetworkObject ? NetworkObject.IsSpawned : false;
+        public bool IsSpawned { get; internal set; }
 
         internal bool IsBehaviourEditable()
         {
@@ -327,12 +353,12 @@ namespace Unity.Netcode
         /// <summary>
         /// Gets the NetworkId of the NetworkObject that owns this NetworkBehaviour
         /// </summary>
-        public ulong NetworkObjectId => NetworkObject.NetworkObjectId;
+        public ulong NetworkObjectId { get; internal set; }
 
         /// <summary>
         /// Gets NetworkId for this NetworkBehaviour from the owner NetworkObject
         /// </summary>
-        public ushort NetworkBehaviourId => NetworkObject.GetNetworkBehaviourOrderIndex(this);
+        public ushort NetworkBehaviourId { get; internal set; }
 
         /// <summary>
         /// Internally caches the Id of this behaviour in a NetworkObject. Makes look-up faster
@@ -352,7 +378,47 @@ namespace Unity.Netcode
         /// <summary>
         /// Gets the ClientId that owns the NetworkObject
         /// </summary>
-        public ulong OwnerClientId => NetworkObject.OwnerClientId;
+        public ulong OwnerClientId { get; internal set; }
+
+        /// <summary>
+        /// Updates properties with network session related
+        /// dependencies such as a NetworkObject's spawned
+        /// state or NetworkManager's session state.
+        /// </summary>
+        internal void UpdateNetworkProperties()
+        {
+            // Set NetworkObject dependent properties
+            if (NetworkObject != null)
+            {
+                // Set identification related properties
+                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);
+
+                // Set ownership related properties
+                IsOwnedByServer = NetworkObject.IsOwnedByServer;
+                IsOwner = NetworkObject.IsOwner;
+                OwnerClientId = NetworkObject.OwnerClientId;
+
+                // Set NetworkManager dependent properties
+                if (NetworkManager != null)
+                {
+                    IsHost = NetworkManager.IsListening && NetworkManager.IsHost;
+                    IsClient = NetworkManager.IsListening && NetworkManager.IsClient;
+                    IsServer = NetworkManager.IsListening && NetworkManager.IsServer;
+                }
+            }
+            else // Shouldn't happen, but if so then set the properties to their default value;
+            {
+                OwnerClientId = NetworkObjectId = default;
+                IsOwnedByServer = IsOwner = IsHost = IsClient = IsServer = default;
+                NetworkBehaviourId = default;
+            }
+        }
 
         /// <summary>
         /// Gets called when the <see cref="NetworkObject"/> gets spawned, message handlers are ready to be registered and the network is setup.
@@ -366,21 +432,41 @@ namespace Unity.Netcode
 
         internal void InternalOnNetworkSpawn()
         {
+            IsSpawned = true;
             InitializeVariables();
+            UpdateNetworkProperties();
+            OnNetworkSpawn();
         }
 
-        internal void InternalOnNetworkDespawn() { }
+        internal void InternalOnNetworkDespawn()
+        {
+            IsSpawned = false;
+            UpdateNetworkProperties();
+            OnNetworkDespawn();
+        }
 
         /// <summary>
         /// Gets called when the local client gains ownership of this object
         /// </summary>
         public virtual void OnGainedOwnership() { }
 
+        internal void InternalOnGainedOwnership()
+        {
+            UpdateNetworkProperties();
+            OnGainedOwnership();
+        }
+
         /// <summary>
         /// Gets called when we loose ownership of this object
         /// </summary>
         public virtual void OnLostOwnership() { }
 
+        internal void InternalOnLostOwnership()
+        {
+            UpdateNetworkProperties();
+            OnLostOwnership();
+        }
+
         /// <summary>
         /// Gets called when the parent NetworkObject of this NetworkBehaviour's NetworkObject has changed
         /// </summary>
@@ -433,12 +519,10 @@ namespace Unity.Netcode
 
             m_VarInit = true;
 
-            FieldInfo[] sortedFields = GetFieldInfoForType(GetType());
-
+            var sortedFields = GetFieldInfoForType(GetType());
             for (int i = 0; i < sortedFields.Length; i++)
             {
-                Type fieldType = sortedFields[i].FieldType;
-
+                var fieldType = sortedFields[i].FieldType;
                 if (fieldType.IsSubclassOf(typeof(NetworkVariableBase)))
                 {
                     var instance = (NetworkVariableBase)sortedFields[i].GetValue(this);
@@ -499,7 +583,7 @@ namespace Unity.Netcode
             }
         }
 
-        internal void VariableUpdate(ulong clientId)
+        internal void VariableUpdate(ulong targetClientId)
         {
             if (!m_VarInit)
             {
@@ -507,37 +591,29 @@ namespace Unity.Netcode
             }
 
             PreNetworkVariableWrite();
-            NetworkVariableUpdate(clientId, NetworkBehaviourId);
+            NetworkVariableUpdate(targetClientId, NetworkBehaviourId);
         }
 
         internal readonly List<int> NetworkVariableIndexesToReset = new List<int>();
         internal readonly HashSet<int> NetworkVariableIndexesToResetSet = new HashSet<int>();
 
-        private void NetworkVariableUpdate(ulong clientId, int behaviourIndex)
+        private void NetworkVariableUpdate(ulong targetClientId, int behaviourIndex)
         {
             if (!CouldHaveDirtyNetworkVariables())
             {
                 return;
             }
 
-            if (NetworkManager.NetworkConfig.UseSnapshotDelta)
-            {
-                for (int k = 0; k < NetworkVariableFields.Count; k++)
-                {
-                    NetworkManager.SnapshotSystem.Store(NetworkObjectId, behaviourIndex, k, NetworkVariableFields[k]);
-                }
-            }
-
-            if (!NetworkManager.NetworkConfig.UseSnapshotDelta)
-            {
             for (int j = 0; j < m_DeliveryMappedNetworkVariableIndices.Count; j++)
             {
                 var shouldSend = false;
                 for (int k = 0; k < NetworkVariableFields.Count; k++)
                 {
-                        if (NetworkVariableFields[k].ShouldWrite(clientId, IsServer))
+                    var networkVariable = NetworkVariableFields[k];
+                    if (networkVariable.IsDirty() && networkVariable.CanClientRead(targetClientId))
                     {
                         shouldSend = true;
+                        break;
                     }
                 }
 
@@ -548,7 +624,7 @@ namespace Unity.Netcode
                         NetworkObjectId = NetworkObjectId,
                         NetworkBehaviourIndex = NetworkObject.GetNetworkBehaviourOrderIndex(this),
                         NetworkBehaviour = this,
-                            ClientId = clientId,
+                        TargetClientId = targetClientId,
                         DeliveryMappedNetworkVariableIndex = m_DeliveryMappedNetworkVariableIndices[j]
                     };
                     // TODO: Serialization is where the IsDirty flag gets changed.
@@ -556,7 +632,7 @@ namespace Unity.Netcode
                     // 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 && clientId == NetworkManager.ServerClientId)
+                    if (IsServer && targetClientId == NetworkManager.ServerClientId)
                     {
                         var tmpWriter = new FastBufferWriter(MessagingSystem.NON_FRAGMENTED_MESSAGE_MAX_SIZE, Allocator.Temp, MessagingSystem.FRAGMENTED_MESSAGE_MAX_SIZE);
                         using (tmpWriter)
@@ -566,8 +642,7 @@ namespace Unity.Netcode
                     }
                     else
                     {
-                            NetworkManager.SendMessage(ref message, m_DeliveryTypesForNetworkVariableGroups[j], clientId);
-                        }
+                        NetworkManager.SendMessage(ref message, m_DeliveryTypesForNetworkVariableGroups[j], targetClientId);
                     }
                 }
             }
@@ -595,7 +670,7 @@ namespace Unity.Netcode
             }
         }
 
-        internal void WriteNetworkVariableData(FastBufferWriter writer, ulong clientId)
+        internal void WriteNetworkVariableData(FastBufferWriter writer, ulong targetClientId)
         {
             if (NetworkVariableFields.Count == 0)
             {
@@ -604,7 +679,7 @@ namespace Unity.Netcode
 
             for (int j = 0; j < NetworkVariableFields.Count; j++)
             {
-                bool canClientRead = NetworkVariableFields[j].CanClientRead(clientId);
+                bool canClientRead = NetworkVariableFields[j].CanClientRead(targetClientId);
 
                 if (canClientRead)
                 {

Runtime/Core/NetworkBehaviourUpdater.cs

@@ -57,7 +57,7 @@ namespace Unity.Netcode
                         {
                             for (int k = 0; k < sobj.ChildNetworkBehaviours.Count; k++)
                             {
-                                sobj.ChildNetworkBehaviours[k].VariableUpdate(networkManager.ServerClientId);
+                                sobj.ChildNetworkBehaviours[k].VariableUpdate(NetworkManager.ServerClientId);
                             }
                         }
                     }

Runtime/Core/NetworkManager.cs

@@ -12,6 +12,7 @@ using Unity.Multiplayer.Tools;
 #endif
 using Unity.Profiling;
 using UnityEngine.SceneManagement;
+using System.Runtime.CompilerServices;
 using Debug = UnityEngine.Debug;
 
 namespace Unity.Netcode
@@ -45,7 +46,7 @@ namespace Unity.Netcode
         private static ProfilerMarker s_TransportDisconnect = new ProfilerMarker($"{nameof(NetworkManager)}.TransportDisconnect");
 #endif
 
-        private const double k_TimeSyncFrequency = 1.0d; // sync every second, TODO will be removed once timesync is done via snapshots
+        private const double k_TimeSyncFrequency = 1.0d; // sync every second
         private const float k_DefaultBufferSizeSec = 0.05f; // todo talk with UX/Product, find good default value for this
 
         internal static string PrefabDebugHelper(NetworkPrefab networkPrefab)
@@ -53,7 +54,6 @@ namespace Unity.Netcode
             return $"{nameof(NetworkPrefab)} \"{networkPrefab.Prefab.gameObject.name}\"";
         }
 
-        internal SnapshotSystem SnapshotSystem { get; private set; }
         internal NetworkBehaviourUpdater BehaviourUpdater { get; private set; }
 
         internal MessagingSystem MessagingSystem { get; private set; }
@@ -125,13 +125,11 @@ namespace Unity.Netcode
             public bool OnVerifyCanReceive(ulong senderId, Type messageType)
             {
                 if (m_NetworkManager.PendingClients.TryGetValue(senderId, out PendingClient client) &&
-                       (client.ConnectionState == PendingClient.State.PendingApproval ||
-                        (client.ConnectionState == PendingClient.State.PendingConnection &&
-                         messageType != typeof(ConnectionRequestMessage))))
+                    (client.ConnectionState == PendingClient.State.PendingApproval || (client.ConnectionState == PendingClient.State.PendingConnection && messageType != typeof(ConnectionRequestMessage))))
                 {
                     if (NetworkLog.CurrentLogLevel <= LogLevel.Normal)
                     {
-                        NetworkLog.LogWarning($"Message received from {nameof(senderId)}={senderId.ToString()} before it has been accepted");
+                        NetworkLog.LogWarning($"Message received from {nameof(senderId)}={senderId} before it has been accepted");
                     }
 
                     return false;
@@ -229,14 +227,12 @@ namespace Unity.Netcode
 
         public NetworkSceneManager SceneManager { get; private set; }
 
-        public readonly ulong ServerClientId = 0;
+        public const ulong ServerClientId = 0;
 
         /// <summary>
         /// Gets the networkId of the server
         /// </summary>
-        private ulong m_ServerTransportId => NetworkConfig.NetworkTransport?.ServerClientId ??
-                                       throw new NullReferenceException(
-                                           $"The transport in the active {nameof(NetworkConfig)} is null");
+        private ulong m_ServerTransportId => NetworkConfig.NetworkTransport?.ServerClientId ?? throw new NullReferenceException($"The transport in the active {nameof(NetworkConfig)} is null");
 
         /// <summary>
         /// Returns ServerClientId if IsServer or LocalClientId if not
@@ -367,16 +363,14 @@ namespace Unity.Netcode
         /// <param name="approved">Whether or not the client was approved</param>
         /// <param name="position">The position to spawn the client at. If null, the prefab position is used.</param>
         /// <param name="rotation">The rotation to spawn the client with. If null, the prefab position is used.</param>
-        public delegate void ConnectionApprovedDelegate(bool createPlayerObject, uint? playerPrefabHash, bool approved,
-            Vector3? position, Quaternion? rotation);
+        public delegate void ConnectionApprovedDelegate(bool createPlayerObject, uint? playerPrefabHash, bool approved, Vector3? position, Quaternion? rotation);
 
         /// <summary>
         /// The callback to invoke during connection approval
         /// </summary>
         public event Action<byte[], ulong, ConnectionApprovedDelegate> ConnectionApprovalCallback = null;
 
-        internal void InvokeConnectionApproval(byte[] payload, ulong clientId, ConnectionApprovedDelegate action) =>
-            ConnectionApprovalCallback?.Invoke(payload, clientId, action);
+        internal void InvokeConnectionApproval(byte[] payload, ulong clientId, ConnectionApprovedDelegate action) => ConnectionApprovalCallback?.Invoke(payload, clientId, action);
 
         /// <summary>
         /// The current NetworkConfig
@@ -565,13 +559,6 @@ namespace Unity.Netcode
 
             NetworkConfig.NetworkTransport.NetworkMetrics = NetworkMetrics;
 
-            //This 'if' should never enter
-            if (SnapshotSystem != null)
-            {
-                SnapshotSystem.Dispose();
-                SnapshotSystem = null;
-            }
-
             if (server)
             {
                 NetworkTimeSystem = NetworkTimeSystem.ServerTimeSystem();
@@ -584,8 +571,6 @@ namespace Unity.Netcode
             NetworkTickSystem = new NetworkTickSystem(NetworkConfig.TickRate, 0, 0);
             NetworkTickSystem.Tick += OnNetworkManagerTick;
 
-            SnapshotSystem = new SnapshotSystem(this, NetworkConfig, NetworkTickSystem);
-
             this.RegisterNetworkUpdate(NetworkUpdateStage.PreUpdate);
 
             // This is used to remove entries not needed or invalid
@@ -800,35 +785,19 @@ namespace Unity.Netcode
         {
             if (NetworkLog.CurrentLogLevel <= LogLevel.Developer)
             {
-                NetworkLog.LogInfo("StartServer()");
+                NetworkLog.LogInfo(nameof(StartServer));
             }
 
-            if (IsServer || IsClient)
+            if (!CanStart(StartType.Server))
             {
-                if (NetworkLog.CurrentLogLevel <= LogLevel.Normal)
-                {
-                    NetworkLog.LogWarning("Cannot start server while an instance is already running");
-                }
-
                 return false;
             }
 
-            if (NetworkConfig.ConnectionApproval)
-            {
-                if (ConnectionApprovalCallback == null)
-                {
-                    if (NetworkLog.CurrentLogLevel <= LogLevel.Normal)
-                    {
-                        NetworkLog.LogWarning(
-                            "No ConnectionApproval callback defined. Connection approval will timeout");
-                    }
-                }
-            }
-
             Initialize(true);
 
-            var result = NetworkConfig.NetworkTransport.StartServer();
-
+            // If we failed to start then shutdown and notify user that the transport failed to start
+            if (NetworkConfig.NetworkTransport.StartServer())
+            {
                 IsServer = true;
                 IsClient = false;
                 IsListening = true;
@@ -836,8 +805,15 @@ namespace Unity.Netcode
                 SpawnManager.ServerSpawnSceneObjectsOnStartSweep();
 
                 OnServerStarted?.Invoke();
+                return true;
+            }
+            else
+            {
+                Debug.LogError($"Server is shutting down due to network transport start failure of {NetworkConfig.NetworkTransport.GetType().Name}!");
+                Shutdown();
+            }
 
-            return result;
+            return false;
         }
 
         /// <summary>
@@ -850,26 +826,26 @@ namespace Unity.Netcode
                 NetworkLog.LogInfo(nameof(StartClient));
             }
 
-            if (IsServer || IsClient)
+            if (!CanStart(StartType.Client))
             {
-                if (NetworkLog.CurrentLogLevel <= LogLevel.Normal)
-                {
-                    NetworkLog.LogWarning("Cannot start client while an instance is already running");
-                }
-
                 return false;
             }
 
             Initialize(false);
             MessagingSystem.ClientConnected(ServerClientId);
 
-            var result = NetworkConfig.NetworkTransport.StartClient();
+            if (!NetworkConfig.NetworkTransport.StartClient())
+            {
+                Debug.LogError($"Client is shutting down due to network transport start failure of {NetworkConfig.NetworkTransport.GetType().Name}!");
+                Shutdown();
+                return false;
+            }
 
             IsServer = false;
             IsClient = true;
             IsListening = true;
 
-            return result;
+            return true;
         }
 
         /// <summary>
@@ -882,31 +858,21 @@ namespace Unity.Netcode
                 NetworkLog.LogInfo(nameof(StartHost));
             }
 
-            if (IsServer || IsClient)
+            if (!CanStart(StartType.Host))
             {
-                if (NetworkLog.CurrentLogLevel <= LogLevel.Normal)
-                {
-                    NetworkLog.LogWarning("Cannot start host while an instance is already running");
-                }
-
                 return false;
             }
 
-            if (NetworkConfig.ConnectionApproval)
-            {
-                if (ConnectionApprovalCallback == null)
-                {
-                    if (NetworkLog.CurrentLogLevel <= LogLevel.Normal)
-                    {
-                        NetworkLog.LogWarning(
-                            "No ConnectionApproval callback defined. Connection approval will timeout");
-                    }
-                }
-            }
-
             Initialize(true);
 
-            var result = NetworkConfig.NetworkTransport.StartServer();
+            // If we failed to start then shutdown and notify user that the transport failed to start
+            if (!NetworkConfig.NetworkTransport.StartServer())
+            {
+                Debug.LogError($"Server is shutting down due to network transport start failure of {NetworkConfig.NetworkTransport.GetType().Name}!");
+                Shutdown();
+                return false;
+            }
+
             MessagingSystem.ClientConnected(ServerClientId);
             LocalClientId = ServerClientId;
             NetworkMetrics.SetConnectionId(LocalClientId);
@@ -942,7 +908,53 @@ namespace Unity.Netcode
 
             OnServerStarted?.Invoke();
 
-            return result;
+            return true;
+        }
+
+        private enum StartType
+        {
+            Server,
+            Host,
+            Client
+        }
+
+        private bool CanStart(StartType type)
+        {
+            if (IsListening)
+            {
+                if (NetworkLog.CurrentLogLevel <= LogLevel.Normal)
+                {
+                    NetworkLog.LogWarning("Cannot start " + type + " while an instance is already running");
+                }
+
+                return false;
+            }
+
+            if (NetworkConfig.ConnectionApproval)
+            {
+                if (ConnectionApprovalCallback == null)
+                {
+                    if (NetworkLog.CurrentLogLevel <= LogLevel.Normal)
+                    {
+                        NetworkLog.LogWarning(
+                            "No ConnectionApproval callback defined. Connection approval will timeout");
+                    }
+                }
+            }
+
+            if (ConnectionApprovalCallback != null)
+            {
+                if (!NetworkConfig.ConnectionApproval)
+                {
+                    if (NetworkLog.CurrentLogLevel <= LogLevel.Normal)
+                    {
+                        NetworkLog.LogWarning(
+                            "A ConnectionApproval callback is defined but ConnectionApproval is disabled. In order to use ConnectionApproval it has to be explicitly enabled ");
+                    }
+                }
+            }
+
+            return true;
         }
 
         public void SetSingleton()
@@ -1014,6 +1026,7 @@ namespace Unity.Netcode
         internal interface INetworkManagerHelper
         {
             bool NotifyUserOfNestedNetworkManager(NetworkManager networkManager, bool ignoreNetworkManagerCache = false, bool editorTest = false);
+            void CheckAndNotifyUserNetworkObjectRemoved(NetworkManager networkManager, bool editorTest = false);
         }
 #endif
 
@@ -1133,12 +1146,6 @@ namespace Unity.Netcode
 
             this.UnregisterAllNetworkUpdates();
 
-            if (SnapshotSystem != null)
-            {
-                SnapshotSystem.Dispose();
-                SnapshotSystem = null;
-            }
-
             if (NetworkTickSystem != null)
             {
                 NetworkTickSystem.Tick -= OnNetworkManagerTick;
@@ -1274,7 +1281,11 @@ namespace Unity.Netcode
             if (!m_ShuttingDown || !m_StopProcessingMessages)
             {
                 MessagingSystem.ProcessSendQueues();
+                NetworkMetrics.UpdateNetworkObjectsCount(SpawnManager.SpawnedObjects.Count);
+                NetworkMetrics.UpdateConnectionsCount((IsServer) ? ConnectedClients.Count : 1);
                 NetworkMetrics.DispatchFrame();
+
+                NetworkObject.VerifyParentingStatus();
             }
             SpawnManager.CleanupStaleTriggers();
 
@@ -1288,7 +1299,6 @@ namespace Unity.Netcode
         /// This function runs once whenever the local tick is incremented and is responsible for the following (in order):
         /// - collect commands/inputs and send them to the server (TBD)
         /// - call NetworkFixedUpdate on all NetworkBehaviours in prediction/client authority mode
-        /// - create a snapshot from resulting state
         /// </summary>
         private void OnNetworkManagerTick()
         {
@@ -1419,18 +1429,15 @@ namespace Unity.Netcode
 #if DEVELOPMENT_BUILD || UNITY_EDITOR
                     s_TransportDisconnect.Begin();
 #endif
-                    clientId = TransportIdToClientId(clientId);
-
-                    OnClientDisconnectCallback?.Invoke(clientId);
-
-                    m_TransportIdToClientIdMap.Remove(transportId);
-                    m_ClientIdToTransportIdMap.Remove(clientId);
+                    clientId = TransportIdCleanUp(clientId, transportId);
 
                     if (NetworkLog.CurrentLogLevel <= LogLevel.Developer)
                     {
                         NetworkLog.LogInfo($"Disconnect Event From {clientId}");
                     }
 
+                    OnClientDisconnectCallback?.Invoke(clientId);
+
                     if (IsServer)
                     {
                         OnClientDisconnectFromServer(clientId);
@@ -1446,6 +1453,31 @@ namespace Unity.Netcode
             }
         }
 
+        /// <summary>
+        /// Handles cleaning up the transport id/client id tables after
+        /// receiving a disconnect event from transport
+        /// </summary>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        private ulong TransportIdCleanUp(ulong clientId, ulong transportId)
+        {
+            // This check is for clients that attempted to connect but failed.
+            // 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 (!IsServer && !m_TransportIdToClientIdMap.ContainsKey(clientId))
+            {
+                return 0;
+            }
+
+            clientId = TransportIdToClientId(clientId);
+
+            m_TransportIdToClientIdMap.Remove(transportId);
+            m_ClientIdToTransportIdMap.Remove(clientId);
+
+            return clientId;
+        }
+
         internal unsafe int SendMessage<TMessageType, TClientIdListType>(ref TMessageType message, NetworkDelivery delivery, in TClientIdListType clientIds)
             where TMessageType : INetworkMessage
             where TClientIdListType : IReadOnlyList<ulong>
@@ -1591,17 +1623,30 @@ namespace Unity.Netcode
                         }
                     }
 
-                    for (int i = networkClient.OwnedObjects.Count - 1; i >= 0; i--)
+                    // Get the NetworkObjects owned by the disconnected client
+                    var clientOwnedObjects = SpawnManager.GetClientOwnedObjects(clientId);
+                    if (clientOwnedObjects == null)
                     {
-                        var ownedObject = networkClient.OwnedObjects[i];
+                        // This could happen if a client is never assigned a player object and is disconnected
+                        // Only log this in verbose/developer mode
+                        if (LogLevel == LogLevel.Developer)
+                        {
+                            NetworkLog.LogWarning($"ClientID {clientId} disconnected with (0) zero owned objects!  Was a player prefab not assigned?");
+                        }
+                    }
+                    else
+                    {
+                        // Handle changing ownership and prefab handlers
+                        for (int i = clientOwnedObjects.Count - 1; i >= 0; i--)
+                        {
+                            var ownedObject = clientOwnedObjects[i];
                             if (ownedObject != null)
                             {
                                 if (!ownedObject.DontDestroyWithOwner)
                                 {
-                                if (PrefabHandler.ContainsHandler(ConnectedClients[clientId].OwnedObjects[i]
-                                    .GlobalObjectIdHash))
+                                    if (PrefabHandler.ContainsHandler(clientOwnedObjects[i].GlobalObjectIdHash))
                                     {
-                                    PrefabHandler.HandleNetworkPrefabDestroy(ConnectedClients[clientId].OwnedObjects[i]);
+                                        PrefabHandler.HandleNetworkPrefabDestroy(clientOwnedObjects[i]);
                                     }
                                     else
                                     {
@@ -1614,9 +1659,9 @@ namespace Unity.Netcode
                                 }
                             }
                         }
+                    }
 
                     // TODO: Could(should?) be replaced with more memory per client, by storing the visibility
-
                     foreach (var sobj in SpawnManager.SpawnedObjectsList)
                     {
                         sobj.Observers.Remove(clientId);
@@ -1764,7 +1809,7 @@ namespace Unity.Netcode
 
                 var message = new CreateObjectMessage
                 {
-                    ObjectInfo = ConnectedClients[clientId].PlayerObject.GetMessageSceneObject(clientPair.Key, false)
+                    ObjectInfo = ConnectedClients[clientId].PlayerObject.GetMessageSceneObject(clientPair.Key)
                 };
                 message.ObjectInfo.Header.Hash = playerPrefabHash;
                 message.ObjectInfo.Header.IsSceneObject = false;

Runtime/Core/NetworkObject.cs

@@ -54,8 +54,6 @@ namespace Unity.Netcode
         /// </summary>
         internal NetworkManager NetworkManagerOwner;
 
-        private ulong m_NetworkObjectId;
-
         /// <summary>
         /// Gets the unique Id of this object that is synced across the network
         /// </summary>
@@ -64,33 +62,7 @@ namespace Unity.Netcode
         /// <summary>
         /// Gets the ClientId of the owner of this NetworkObject
         /// </summary>
-        public ulong OwnerClientId
-        {
-            get
-            {
-                if (OwnerClientIdInternal == null)
-                {
-                    return NetworkManager != null ? NetworkManager.ServerClientId : 0;
-                }
-                else
-                {
-                    return OwnerClientIdInternal.Value;
-                }
-            }
-            internal set
-            {
-                if (NetworkManager != null && value == NetworkManager.ServerClientId)
-                {
-                    OwnerClientIdInternal = null;
-                }
-                else
-                {
-                    OwnerClientIdInternal = value;
-                }
-            }
-        }
-
-        internal ulong? OwnerClientIdInternal = null;
+        public ulong OwnerClientId { get; internal set; }
 
         /// <summary>
         /// If true, the object will always be replicated as root on clients and the parent will be ignored.
@@ -234,11 +206,6 @@ namespace Unity.Netcode
                 throw new VisibilityChangeException("The object is already visible");
             }
 
-            if (NetworkManager.NetworkConfig.UseSnapshotSpawn)
-            {
-                SnapshotSpawn(clientId);
-            }
-
             Observers.Add(clientId);
 
             NetworkManager.SpawnManager.SendSpawnCallForObject(clientId, this);
@@ -314,15 +281,8 @@ namespace Unity.Netcode
                 throw new VisibilityChangeException("Cannot hide an object from the server");
             }
 
-
             Observers.Remove(clientId);
 
-            if (NetworkManager.NetworkConfig.UseSnapshotSpawn)
-            {
-                SnapshotDespawn(clientId);
-            }
-            else
-            {
             var message = new DestroyObjectMessage
             {
                 NetworkObjectId = NetworkObjectId
@@ -331,7 +291,6 @@ namespace Unity.Netcode
             var size = NetworkManager.SendMessage(ref message, NetworkDelivery.ReliableSequenced, clientId);
             NetworkManager.NetworkMetrics.TrackObjectDestroySent(clientId, this, size);
         }
-        }
 
         /// <summary>
         /// Hides a list of objects from a client
@@ -345,14 +304,14 @@ namespace Unity.Netcode
                 throw new ArgumentNullException("At least one " + nameof(NetworkObject) + " has to be provided");
             }
 
-            NetworkManager networkManager = networkObjects[0].NetworkManager;
+            var networkManager = networkObjects[0].NetworkManager;
 
             if (!networkManager.IsServer)
             {
                 throw new NotServerException("Only server can change visibility");
             }
 
-            if (clientId == networkManager.ServerClientId)
+            if (clientId == NetworkManager.ServerClientId)
             {
                 throw new VisibilityChangeException("Cannot hide an object from the server");
             }
@@ -384,84 +343,21 @@ namespace Unity.Netcode
 
         private void OnDestroy()
         {
-            if (NetworkManager != null && NetworkManager.IsListening && NetworkManager.IsServer == false && IsSpawned
-                && (IsSceneObject == null || (IsSceneObject != null && IsSceneObject.Value != true)))
+            if (NetworkManager != null && NetworkManager.IsListening && NetworkManager.IsServer == false && IsSpawned &&
+                (IsSceneObject == null || (IsSceneObject != null && IsSceneObject.Value != true)))
             {
                 throw new NotServerException($"Destroy a spawned {nameof(NetworkObject)} on a non-host client is not valid. Call {nameof(Destroy)} or {nameof(Despawn)} on the server/host instead.");
             }
 
-            if (NetworkManager != null && NetworkManager.SpawnManager != null && NetworkManager.SpawnManager.SpawnedObjects.TryGetValue(NetworkObjectId, out var networkObject))
+            if (NetworkManager != null && NetworkManager.SpawnManager != null &&
+                NetworkManager.SpawnManager.SpawnedObjects.TryGetValue(NetworkObjectId, out var networkObject))
             {
                 NetworkManager.SpawnManager.OnDespawnObject(networkObject, false);
             }
         }
 
-        private SnapshotDespawnCommand GetDespawnCommand()
-        {
-            var command = new SnapshotDespawnCommand();
-            command.NetworkObjectId = NetworkObjectId;
-
-            return command;
-        }
-
-        private SnapshotSpawnCommand GetSpawnCommand()
-        {
-            var command = new SnapshotSpawnCommand();
-            command.NetworkObjectId = NetworkObjectId;
-            command.OwnerClientId = OwnerClientId;
-            command.IsPlayerObject = IsPlayerObject;
-            command.IsSceneObject = (IsSceneObject == null) || IsSceneObject.Value;
-
-            ulong? parent = NetworkManager.SpawnManager.GetSpawnParentId(this);
-            if (parent != null)
-            {
-                command.ParentNetworkId = parent.Value;
-            }
-            else
-            {
-                // write own network id, when no parents. todo: optimize this.
-                command.ParentNetworkId = command.NetworkObjectId;
-            }
-
-            command.GlobalObjectIdHash = HostCheckForGlobalObjectIdHashOverride();
-            // todo: check if (IncludeTransformWhenSpawning == null || IncludeTransformWhenSpawning(clientId)) for any clientId
-            command.ObjectPosition = transform.position;
-            command.ObjectRotation = transform.rotation;
-            command.ObjectScale = transform.localScale;
-
-            return command;
-        }
-
-        private void SnapshotSpawn()
-        {
-            var command = GetSpawnCommand();
-            NetworkManager.SnapshotSystem.Spawn(command);
-        }
-
-        private void SnapshotSpawn(ulong clientId)
-        {
-            var command = GetSpawnCommand();
-            command.TargetClientIds = new List<ulong>();
-            command.TargetClientIds.Add(clientId);
-            NetworkManager.SnapshotSystem.Spawn(command);
-        }
-
-        internal void SnapshotDespawn()
-        {
-            var command = GetDespawnCommand();
-            NetworkManager.SnapshotSystem.Despawn(command);
-        }
-
-        internal void SnapshotDespawn(ulong clientId)
-        {
-            var command = GetDespawnCommand();
-            command.TargetClientIds = new List<ulong>();
-            command.TargetClientIds.Add(clientId);
-            NetworkManager.SnapshotSystem.Despawn(command);
-        }
-
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        private void SpawnInternal(bool destroyWithScene, ulong? ownerClientId, bool playerObject)
+        private void SpawnInternal(bool destroyWithScene, ulong ownerClientId, bool playerObject)
         {
             if (!NetworkManager.IsListening)
             {
@@ -475,12 +371,6 @@ namespace Unity.Netcode
 
             NetworkManager.SpawnManager.SpawnNetworkObjectLocally(this, NetworkManager.SpawnManager.GetNetworkObjectId(), false, playerObject, ownerClientId, destroyWithScene);
 
-            if (NetworkManager.NetworkConfig.UseSnapshotSpawn)
-            {
-                SnapshotSpawn();
-            }
-
-            ulong ownerId = ownerClientId != null ? ownerClientId.Value : NetworkManager.ServerClientId;
             for (int i = 0; i < NetworkManager.ConnectedClientsList.Count; i++)
             {
                 if (Observers.Contains(NetworkManager.ConnectedClientsList[i].ClientId))
@@ -496,7 +386,7 @@ namespace Unity.Netcode
         /// <param name="destroyWithScene">Should the object be destroyed when the scene is changed</param>
         public void Spawn(bool destroyWithScene = false)
         {
-            SpawnInternal(destroyWithScene, null, false);
+            SpawnInternal(destroyWithScene, NetworkManager.ServerClientId, false);
         }
 
         /// <summary>
@@ -547,17 +437,29 @@ namespace Unity.Netcode
 
         internal void InvokeBehaviourOnLostOwnership()
         {
+            // Server already handles this earlier, hosts should ignore, all clients should update
+            if (!NetworkManager.IsServer)
+            {
+                NetworkManager.SpawnManager.UpdateOwnershipTable(this, OwnerClientId, true);
+            }
+
             for (int i = 0; i < ChildNetworkBehaviours.Count; i++)
             {
-                ChildNetworkBehaviours[i].OnLostOwnership();
+                ChildNetworkBehaviours[i].InternalOnLostOwnership();
             }
         }
 
         internal void InvokeBehaviourOnGainedOwnership()
         {
+            // Server already handles this earlier, hosts should ignore and only client owners should update
+            if (!NetworkManager.IsServer && NetworkManager.LocalClientId == OwnerClientId)
+            {
+                NetworkManager.SpawnManager.UpdateOwnershipTable(this, OwnerClientId);
+            }
+
             for (int i = 0; i < ChildNetworkBehaviours.Count; i++)
             {
-                ChildNetworkBehaviours[i].OnGainedOwnership();
+                ChildNetworkBehaviours[i].InternalOnGainedOwnership();
             }
         }
 
@@ -756,13 +658,7 @@ namespace Unity.Netcode
 
             if (!NetworkManager.SpawnManager.SpawnedObjects.ContainsKey(m_LatestParent.Value))
             {
-                if (OrphanChildren.Add(this))
-                {
-                    if (NetworkLog.CurrentLogLevel <= LogLevel.Normal)
-                    {
-                        NetworkLog.LogWarning($"{nameof(NetworkObject)} ({name}) cannot find its parent, added to {nameof(OrphanChildren)} set");
-                    }
-                }
+                OrphanChildren.Add(this);
                 return false;
             }
 
@@ -793,19 +689,21 @@ namespace Unity.Netcode
 
         internal void InvokeBehaviourNetworkSpawn()
         {
+            NetworkManager.SpawnManager.UpdateOwnershipTable(this, OwnerClientId);
+
             for (int i = 0; i < ChildNetworkBehaviours.Count; i++)
             {
                 ChildNetworkBehaviours[i].InternalOnNetworkSpawn();
-                ChildNetworkBehaviours[i].OnNetworkSpawn();
             }
         }
 
         internal void InvokeBehaviourNetworkDespawn()
         {
+            NetworkManager.SpawnManager.UpdateOwnershipTable(this, OwnerClientId, true);
+
             for (int i = 0; i < ChildNetworkBehaviours.Count; i++)
             {
                 ChildNetworkBehaviours[i].InternalOnNetworkDespawn();
-                ChildNetworkBehaviours[i].OnNetworkDespawn();
             }
         }
 
@@ -834,13 +732,13 @@ namespace Unity.Netcode
             }
         }
 
-        internal void WriteNetworkVariableData(FastBufferWriter writer, ulong clientId)
+        internal void WriteNetworkVariableData(FastBufferWriter writer, ulong targetClientId)
         {
             for (int i = 0; i < ChildNetworkBehaviours.Count; i++)
             {
                 var behavior = ChildNetworkBehaviours[i];
                 behavior.InitializeVariables();
-                behavior.WriteNetworkVariableData(writer, clientId);
+                behavior.WriteNetworkVariableData(writer, targetClientId);
             }
         }
 
@@ -853,6 +751,27 @@ namespace Unity.Netcode
             }
         }
 
+        // NGO currently guarantees that the client will receive spawn data for all objects in one network tick.
+        //  Children may arrive before their parents; when they do they are stored in OrphanedChildren and then
+        //  resolved when their parents arrived.  Because we don't send a partial list of spawns (yet), something
+        //  has gone wrong if by the end of an update we still have unresolved orphans
+        //
+
+        // if and when we have different systems for where it is expected that orphans survive across ticks,
+        //   then this warning will remind us that we need to revamp the system because then we can no longer simply
+        //   spawn the orphan without its parent (at least, not when its transform is set to local coords mode)
+        //   - because then you’ll have children popping at the wrong location not having their parent’s global position to root them
+        //   - and then they’ll pop to the correct location after they get the parent, and that would be not good
+        internal static void VerifyParentingStatus()
+        {
+            if (NetworkLog.CurrentLogLevel <= LogLevel.Normal)
+            {
+                if (OrphanChildren.Count > 0)
+                {
+                    NetworkLog.LogWarning($"{nameof(NetworkObject)} ({OrphanChildren.Count}) children not resolved to parents by the end of frame");
+                }
+            }
+        }
         internal void SetNetworkVariableData(FastBufferReader reader)
         {
             for (int i = 0; i < ChildNetworkBehaviours.Count; i++)
@@ -918,7 +837,6 @@ namespace Unity.Netcode
                 public bool IsSceneObject;
                 public bool HasTransform;
                 public bool IsReparented;
-                public bool HasNetworkVariables;
             }
 
             public HeaderData Header;
@@ -979,11 +897,8 @@ namespace Unity.Netcode
                     }
                 }
 
-                if (Header.HasNetworkVariables)
-                {
                 OwnerObject.WriteNetworkVariableData(writer, TargetClientId);
             }
-            }
 
             public unsafe void Deserialize(FastBufferReader reader)
             {
@@ -1022,7 +937,7 @@ namespace Unity.Netcode
             }
         }
 
-        internal SceneObject GetMessageSceneObject(ulong targetClientId, bool includeNetworkVariableData = true)
+        internal SceneObject GetMessageSceneObject(ulong targetClientId)
         {
             var obj = new SceneObject
             {
@@ -1033,7 +948,6 @@ namespace Unity.Netcode
                     OwnerClientId = OwnerClientId,
                     IsSceneObject = IsSceneObject ?? true,
                     Hash = HostCheckForGlobalObjectIdHashOverride(),
-                    HasNetworkVariables = includeNetworkVariableData
                 },
                 OwnerObject = this,
                 TargetClientId = targetClientId

Runtime/Core/SnapshotRtt.cs

@@ -1,93 +0,0 @@
-using System;
-
-namespace Unity.Netcode
-{
-    internal class ConnectionRtt
-    {
-        private double[] m_RttSendTimes; // times at which packet were sent for RTT computations
-        private int[] m_SendSequence; // tick, or other key, at which packets were sent (to allow matching)
-        private double[] m_MeasuredLatencies; // measured latencies (ring buffer)
-        private int m_LatenciesBegin = 0; // ring buffer begin
-        private int m_LatenciesEnd = 0; // ring buffer end
-
-        /// <summary>
-        /// Round-trip-time data
-        /// </summary>
-        public struct Rtt
-        {
-            public double BestSec; // best RTT
-            public double AverageSec; // average RTT
-            public double WorstSec; // worst RTT
-            public double LastSec; // latest ack'ed RTT
-            public int SampleCount; // number of contributing samples
-        }
-
-        public ConnectionRtt()
-        {
-            m_RttSendTimes = new double[NetworkConfig.RttWindowSize];
-            m_SendSequence = new int[NetworkConfig.RttWindowSize];
-            m_MeasuredLatencies = new double[NetworkConfig.RttWindowSize];
-        }
-
-        /// <summary>
-        /// Returns the Round-trip-time computation for this client
-        /// </summary>
-        public Rtt GetRtt()
-        {
-            var ret = new Rtt();
-            var index = m_LatenciesBegin;
-            double total = 0.0;
-            ret.BestSec = m_MeasuredLatencies[m_LatenciesBegin];
-            ret.WorstSec = m_MeasuredLatencies[m_LatenciesBegin];
-
-            while (index != m_LatenciesEnd)
-            {
-                total += m_MeasuredLatencies[index];
-                ret.SampleCount++;
-                ret.BestSec = Math.Min(ret.BestSec, m_MeasuredLatencies[index]);
-                ret.WorstSec = Math.Max(ret.WorstSec, m_MeasuredLatencies[index]);
-                index = (index + 1) % NetworkConfig.RttAverageSamples;
-            }
-
-            if (ret.SampleCount != 0)
-            {
-                ret.AverageSec = total / ret.SampleCount;
-                // the latest RTT is one before m_LatenciesEnd
-                ret.LastSec = m_MeasuredLatencies[(m_LatenciesEnd + (NetworkConfig.RttWindowSize - 1)) % NetworkConfig.RttWindowSize];
-            }
-            else
-            {
-                ret.AverageSec = 0;
-                ret.BestSec = 0;
-                ret.WorstSec = 0;
-                ret.SampleCount = 0;
-                ret.LastSec = 0;
-            }
-
-            return ret;
-        }
-
-        internal void NotifySend(int sequence, double timeSec)
-        {
-            m_RttSendTimes[sequence % NetworkConfig.RttWindowSize] = timeSec;
-            m_SendSequence[sequence % NetworkConfig.RttWindowSize] = sequence;
-        }
-
-        internal void NotifyAck(int sequence, double timeSec)
-        {
-            // if the same slot was not used by a later send
-            if (m_SendSequence[sequence % NetworkConfig.RttWindowSize] == sequence)
-            {
-                double latency = timeSec - m_RttSendTimes[sequence % NetworkConfig.RttWindowSize];
-
-                m_MeasuredLatencies[m_LatenciesEnd] = latency;
-                m_LatenciesEnd = (m_LatenciesEnd + 1) % NetworkConfig.RttAverageSamples;
-
-                if (m_LatenciesEnd == m_LatenciesBegin)
-                {
-                    m_LatenciesBegin = (m_LatenciesBegin + 1) % NetworkConfig.RttAverageSamples;
-                }
-            }
-        }
-    }
-}

Runtime/Logging/NetworkLog.cs

@@ -14,9 +14,9 @@ namespace Unity.Netcode
         public static LogLevel CurrentLogLevel => NetworkManager.Singleton == null ? LogLevel.Normal : NetworkManager.Singleton.LogLevel;
 
         // internal logging
-        internal static void LogInfo(string message) => Debug.Log($"[Netcode] {message}");
-        internal static void LogWarning(string message) => Debug.LogWarning($"[Netcode] {message}");
-        internal static void LogError(string message) => Debug.LogError($"[Netcode] {message}");
+        public static void LogInfo(string message) => Debug.Log($"[Netcode] {message}");
+        public static void LogWarning(string message) => Debug.LogWarning($"[Netcode] {message}");
+        public static void LogError(string message) => Debug.LogError($"[Netcode] {message}");
 
         /// <summary>
         /// Logs an info log locally and on the server if possible.
@@ -62,9 +62,9 @@ namespace Unity.Netcode
                     LogType = logType,
                     Message = message
                 };
-                var size = NetworkManager.Singleton.SendMessage(ref networkMessage, NetworkDelivery.ReliableFragmentedSequenced, NetworkManager.Singleton.ServerClientId);
+                var size = NetworkManager.Singleton.SendMessage(ref networkMessage, NetworkDelivery.ReliableFragmentedSequenced, NetworkManager.ServerClientId);
 
-                NetworkManager.Singleton.NetworkMetrics.TrackServerLogSent(NetworkManager.Singleton.ServerClientId, (uint)logType, size);
+                NetworkManager.Singleton.NetworkMetrics.TrackServerLogSent(NetworkManager.ServerClientId, (uint)logType, size);
             }
         }
 

Runtime/Messaging/Messages/ChangeOwnershipMessage.cs

@@ -29,24 +29,33 @@ namespace Unity.Netcode
 
         public void Handle(ref NetworkContext context)
         {
-
             var networkManager = (NetworkManager)context.SystemOwner;
             var networkObject = networkManager.SpawnManager.SpawnedObjects[NetworkObjectId];
-
-            if (networkObject.OwnerClientId == networkManager.LocalClientId)
-            {
-                //We are current owner.
-                networkObject.InvokeBehaviourOnLostOwnership();
-            }
+            var originalOwner = networkObject.OwnerClientId;
 
             networkObject.OwnerClientId = OwnerClientId;
 
+            // We are current owner.
+            if (originalOwner == networkManager.LocalClientId)
+            {
+                networkObject.InvokeBehaviourOnLostOwnership();
+            }
+
+            // We are new owner.
             if (OwnerClientId == networkManager.LocalClientId)
             {
-                //We are new owner.
                 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)
+            {
+                for (int i = 0; i < networkObject.ChildNetworkBehaviours.Count; i++)
+                {
+                    networkObject.ChildNetworkBehaviours[i].UpdateNetworkProperties();
+                }
+            }
+
             networkManager.NetworkMetrics.TrackOwnershipChangeReceived(context.SenderId, networkObject, context.MessageSize);
         }
     }

Runtime/Messaging/Messages/NetworkVariableDeltaMessage.cs

@@ -16,7 +16,7 @@ namespace Unity.Netcode
         public ushort NetworkBehaviourIndex;
 
         public HashSet<int> DeliveryMappedNetworkVariableIndex;
-        public ulong ClientId;
+        public ulong TargetClientId;
         public NetworkBehaviour NetworkBehaviour;
 
         private FastBufferReader m_ReceivedNetworkVariableData;
@@ -31,9 +31,9 @@ namespace Unity.Netcode
             writer.WriteValue(NetworkObjectId);
             writer.WriteValue(NetworkBehaviourIndex);
 
-            for (int k = 0; k < NetworkBehaviour.NetworkVariableFields.Count; k++)
+            for (int i = 0; i < NetworkBehaviour.NetworkVariableFields.Count; i++)
             {
-                if (!DeliveryMappedNetworkVariableIndex.Contains(k))
+                if (!DeliveryMappedNetworkVariableIndex.Contains(i))
                 {
                     // This var does not belong to the currently iterating delivery group.
                     if (NetworkBehaviour.NetworkManager.NetworkConfig.EnsureNetworkVariableLengthSafety)
@@ -48,15 +48,17 @@ namespace Unity.Netcode
                     continue;
                 }
 
-                //   if I'm dirty AND a client, write (server always has all permissions)
-                //   if I'm dirty AND the server AND the client can read me, send.
-                bool shouldWrite = NetworkBehaviour.NetworkVariableFields[k].ShouldWrite(ClientId, NetworkBehaviour.NetworkManager.IsServer);
+                var startingSize = writer.Length;
+                var networkVariable = NetworkBehaviour.NetworkVariableFields[i];
+                var shouldWrite = networkVariable.IsDirty() &&
+                    networkVariable.CanClientRead(TargetClientId) &&
+                    (NetworkBehaviour.NetworkManager.IsServer || networkVariable.CanClientWrite(NetworkBehaviour.NetworkManager.LocalClientId));
 
                 if (NetworkBehaviour.NetworkManager.NetworkConfig.EnsureNetworkVariableLengthSafety)
                 {
                     if (!shouldWrite)
                     {
-                        writer.WriteValueSafe((ushort)0);
+                        BytePacker.WriteValueBitPacked(writer, 0);
                     }
                 }
                 else
@@ -68,34 +70,34 @@ namespace Unity.Netcode
                 {
                     if (NetworkBehaviour.NetworkManager.NetworkConfig.EnsureNetworkVariableLengthSafety)
                     {
-                        var tmpWriter = new FastBufferWriter(MessagingSystem.NON_FRAGMENTED_MESSAGE_MAX_SIZE, Allocator.Temp, short.MaxValue);
-                        NetworkBehaviour.NetworkVariableFields[k].WriteDelta(tmpWriter);
+                        var tempWriter = new FastBufferWriter(MessagingSystem.NON_FRAGMENTED_MESSAGE_MAX_SIZE, Allocator.Temp, MessagingSystem.FRAGMENTED_MESSAGE_MAX_SIZE);
+                        NetworkBehaviour.NetworkVariableFields[i].WriteDelta(tempWriter);
+                        BytePacker.WriteValueBitPacked(writer, tempWriter.Length);
 
-                        if (!writer.TryBeginWrite(FastBufferWriter.GetWriteSize<ushort>() + tmpWriter.Length))
+                        if (!writer.TryBeginWrite(tempWriter.Length))
                         {
                             throw new OverflowException($"Not enough space in the buffer to write {nameof(NetworkVariableDeltaMessage)}");
                         }
 
-                        writer.WriteValue((ushort)tmpWriter.Length);
-                        tmpWriter.CopyTo(writer);
+                        tempWriter.CopyTo(writer);
                     }
                     else
                     {
-                        NetworkBehaviour.NetworkVariableFields[k].WriteDelta(writer);
+                        networkVariable.WriteDelta(writer);
                     }
 
-                    if (!NetworkBehaviour.NetworkVariableIndexesToResetSet.Contains(k))
+                    if (!NetworkBehaviour.NetworkVariableIndexesToResetSet.Contains(i))
                     {
-                        NetworkBehaviour.NetworkVariableIndexesToResetSet.Add(k);
-                        NetworkBehaviour.NetworkVariableIndexesToReset.Add(k);
+                        NetworkBehaviour.NetworkVariableIndexesToResetSet.Add(i);
+                        NetworkBehaviour.NetworkVariableIndexesToReset.Add(i);
                     }
 
                     NetworkBehaviour.NetworkManager.NetworkMetrics.TrackNetworkVariableDeltaSent(
-                        ClientId,
+                        TargetClientId,
                         NetworkBehaviour.NetworkObject,
-                        NetworkBehaviour.NetworkVariableFields[k].Name,
+                        networkVariable.Name,
                         NetworkBehaviour.__getTypeName(),
-                        writer.Length);
+                        writer.Length - startingSize);
                 }
             }
         }
@@ -121,9 +123,9 @@ namespace Unity.Netcode
 
             if (networkManager.SpawnManager.SpawnedObjects.TryGetValue(NetworkObjectId, out NetworkObject networkObject))
             {
-                NetworkBehaviour behaviour = networkObject.GetNetworkBehaviourAtOrderIndex(NetworkBehaviourIndex);
+                var networkBehaviour = networkObject.GetNetworkBehaviourAtOrderIndex(NetworkBehaviourIndex);
 
-                if (behaviour == null)
+                if (networkBehaviour == null)
                 {
                     if (NetworkLog.CurrentLogLevel <= LogLevel.Normal)
                     {
@@ -132,13 +134,12 @@ namespace Unity.Netcode
                 }
                 else
                 {
-                    for (int i = 0; i < behaviour.NetworkVariableFields.Count; i++)
+                    for (int i = 0; i < networkBehaviour.NetworkVariableFields.Count; i++)
                     {
-                        ushort varSize = 0;
-
+                        int varSize = 0;
                         if (networkManager.NetworkConfig.EnsureNetworkVariableLengthSafety)
                         {
-                            m_ReceivedNetworkVariableData.ReadValueSafe(out varSize);
+                            ByteUnpacker.ReadValueBitPacked(m_ReceivedNetworkVariableData, out varSize);
 
                             if (varSize == 0)
                             {
@@ -154,15 +155,17 @@ namespace Unity.Netcode
                             }
                         }
 
-                        if (networkManager.IsServer)
+                        var networkVariable = networkBehaviour.NetworkVariableFields[i];
+
+                        if (networkManager.IsServer && !networkVariable.CanClientWrite(context.SenderId))
                         {
                             // we are choosing not to fire an exception here, because otherwise a malicious client could use this to crash the server
                             if (networkManager.NetworkConfig.EnsureNetworkVariableLengthSafety)
                             {
-                                if (NetworkLog.CurrentLogLevel <= LogLevel.Normal)
+                                if (NetworkLog.CurrentLogLevel <= LogLevel.Developer)
                                 {
-                                    NetworkLog.LogWarning($"Client wrote to {typeof(NetworkVariable<>).Name} without permission. => {nameof(NetworkObjectId)}: {NetworkObjectId} - {nameof(NetworkObject.GetNetworkBehaviourOrderIndex)}(): {networkObject.GetNetworkBehaviourOrderIndex(behaviour)} - VariableIndex: {i}");
-                                    NetworkLog.LogError($"[{behaviour.NetworkVariableFields[i].GetType().Name}]");
+                                    NetworkLog.LogWarning($"Client wrote to {typeof(NetworkVariable<>).Name} without permission. => {nameof(NetworkObjectId)}: {NetworkObjectId} - {nameof(NetworkObject.GetNetworkBehaviourOrderIndex)}(): {networkObject.GetNetworkBehaviourOrderIndex(networkBehaviour)} - VariableIndex: {i}");
+                                    NetworkLog.LogError($"[{networkVariable.GetType().Name}]");
                                 }
 
                                 m_ReceivedNetworkVariableData.Seek(m_ReceivedNetworkVariableData.Position + varSize);
@@ -176,23 +179,23 @@ namespace Unity.Netcode
                             //A dummy read COULD be added to the interface for this situation, but it's just being too nice.
                             //This is after all a developer fault. A critical error should be fine.
                             // - TwoTen
-                            if (NetworkLog.CurrentLogLevel <= LogLevel.Error)
+                            if (NetworkLog.CurrentLogLevel <= LogLevel.Developer)
                             {
-                                NetworkLog.LogError($"Client wrote to {typeof(NetworkVariable<>).Name} without permission. No more variables can be read. This is critical. => {nameof(NetworkObjectId)}: {NetworkObjectId} - {nameof(NetworkObject.GetNetworkBehaviourOrderIndex)}(): {networkObject.GetNetworkBehaviourOrderIndex(behaviour)} - VariableIndex: {i}");
-                                NetworkLog.LogError($"[{behaviour.NetworkVariableFields[i].GetType().Name}]");
+                                NetworkLog.LogError($"Client wrote to {typeof(NetworkVariable<>).Name} without permission. No more variables can be read. This is critical. => {nameof(NetworkObjectId)}: {NetworkObjectId} - {nameof(NetworkObject.GetNetworkBehaviourOrderIndex)}(): {networkObject.GetNetworkBehaviourOrderIndex(networkBehaviour)} - VariableIndex: {i}");
+                                NetworkLog.LogError($"[{networkVariable.GetType().Name}]");
                             }
 
                             return;
                         }
                         int readStartPos = m_ReceivedNetworkVariableData.Position;
 
-                        behaviour.NetworkVariableFields[i].ReadDelta(m_ReceivedNetworkVariableData, networkManager.IsServer);
+                        networkVariable.ReadDelta(m_ReceivedNetworkVariableData, networkManager.IsServer);
 
                         networkManager.NetworkMetrics.TrackNetworkVariableDeltaReceived(
                             context.SenderId,
                             networkObject,
-                            behaviour.NetworkVariableFields[i].Name,
-                            behaviour.__getTypeName(),
+                            networkVariable.Name,
+                            networkBehaviour.__getTypeName(),
                             context.MessageSize);
 
 
@@ -202,7 +205,7 @@ namespace Unity.Netcode
                             {
                                 if (NetworkLog.CurrentLogLevel <= LogLevel.Normal)
                                 {
-                                    NetworkLog.LogWarning($"Var delta read too far. {m_ReceivedNetworkVariableData.Position - (readStartPos + varSize)} bytes. => {nameof(NetworkObjectId)}: {NetworkObjectId} - {nameof(NetworkObject.GetNetworkBehaviourOrderIndex)}(): {networkObject.GetNetworkBehaviourOrderIndex(behaviour)} - VariableIndex: {i}");
+                                    NetworkLog.LogWarning($"Var delta read too far. {m_ReceivedNetworkVariableData.Position - (readStartPos + varSize)} bytes. => {nameof(NetworkObjectId)}: {NetworkObjectId} - {nameof(NetworkObject.GetNetworkBehaviourOrderIndex)}(): {networkObject.GetNetworkBehaviourOrderIndex(networkBehaviour)} - VariableIndex: {i}");
                                 }
 
                                 m_ReceivedNetworkVariableData.Seek(readStartPos + varSize);
@@ -211,7 +214,7 @@ namespace Unity.Netcode
                             {
                                 if (NetworkLog.CurrentLogLevel <= LogLevel.Normal)
                                 {
-                                    NetworkLog.LogWarning($"Var delta read too little. {(readStartPos + varSize) - m_ReceivedNetworkVariableData.Position} bytes. => {nameof(NetworkObjectId)}: {NetworkObjectId} - {nameof(NetworkObject.GetNetworkBehaviourOrderIndex)}(): {networkObject.GetNetworkBehaviourOrderIndex(behaviour)} - VariableIndex: {i}");
+                                    NetworkLog.LogWarning($"Var delta read too little. {readStartPos + varSize - m_ReceivedNetworkVariableData.Position} bytes. => {nameof(NetworkObjectId)}: {NetworkObjectId} - {nameof(NetworkObject.GetNetworkBehaviourOrderIndex)}(): {networkObject.GetNetworkBehaviourOrderIndex(networkBehaviour)} - VariableIndex: {i}");
                                 }
 
                                 m_ReceivedNetworkVariableData.Seek(readStartPos + varSize);

Runtime/Messaging/Messages/SnapshotDataMessage.cs

@@ -1,160 +0,0 @@
-using System;
-using Unity.Collections;
-using Unity.Collections.LowLevel.Unsafe;
-using UnityEngine;
-
-namespace Unity.Netcode
-{
-    internal struct SnapshotDataMessage : INetworkMessage
-    {
-        public int CurrentTick;
-        public ushort Sequence;
-
-        public ushort Range;
-
-        public byte[] SendMainBuffer;
-        public NativeArray<byte> ReceiveMainBuffer;
-
-        public struct AckData
-        {
-            public ushort LastReceivedSequence;
-            public ushort ReceivedSequenceMask;
-        }
-
-        public AckData Ack;
-
-        public struct EntryData
-        {
-            public ulong NetworkObjectId;
-            public ushort BehaviourIndex;
-            public ushort VariableIndex;
-            public int TickWritten;
-            public ushort Position;
-            public ushort Length;
-        }
-
-        public NativeList<EntryData> Entries;
-
-        public struct SpawnData
-        {
-            public ulong NetworkObjectId;
-            public uint Hash;
-            public bool IsSceneObject;
-
-            public bool IsPlayerObject;
-            public ulong OwnerClientId;
-            public ulong ParentNetworkId;
-            public Vector3 Position;
-            public Quaternion Rotation;
-            public Vector3 Scale;
-
-            public int TickWritten;
-        }
-
-        public NativeList<SpawnData> Spawns;
-
-        public struct DespawnData
-        {
-            public ulong NetworkObjectId;
-            public int TickWritten;
-        }
-
-        public NativeList<DespawnData> Despawns;
-
-        public unsafe void Serialize(FastBufferWriter writer)
-        {
-            if (!writer.TryBeginWrite(
-                FastBufferWriter.GetWriteSize(CurrentTick) +
-                FastBufferWriter.GetWriteSize(Sequence) +
-                FastBufferWriter.GetWriteSize(Range) + Range +
-                FastBufferWriter.GetWriteSize(Ack) +
-                FastBufferWriter.GetWriteSize<ushort>() +
-                Entries.Length * sizeof(EntryData) +
-                FastBufferWriter.GetWriteSize<ushort>() +
-                Spawns.Length * sizeof(SpawnData) +
-                FastBufferWriter.GetWriteSize<ushort>() +
-                Despawns.Length * sizeof(DespawnData)
-            ))
-            {
-                throw new OverflowException($"Not enough space to serialize {nameof(SnapshotDataMessage)}");
-            }
-            writer.WriteValue(CurrentTick);
-            writer.WriteValue(Sequence);
-
-            writer.WriteValue(Range);
-            writer.WriteBytes(SendMainBuffer, Range);
-            writer.WriteValue(Ack);
-
-            writer.WriteValue((ushort)Entries.Length);
-            writer.WriteBytes((byte*)Entries.GetUnsafePtr(), Entries.Length * sizeof(EntryData));
-
-            writer.WriteValue((ushort)Spawns.Length);
-            writer.WriteBytes((byte*)Spawns.GetUnsafePtr(), Spawns.Length * sizeof(SpawnData));
-
-            writer.WriteValue((ushort)Despawns.Length);
-            writer.WriteBytes((byte*)Despawns.GetUnsafePtr(), Despawns.Length * sizeof(DespawnData));
-        }
-
-        public unsafe bool Deserialize(FastBufferReader reader, ref NetworkContext context)
-        {
-            if (!reader.TryBeginRead(
-                FastBufferWriter.GetWriteSize(CurrentTick) +
-                FastBufferWriter.GetWriteSize(Sequence) +
-                FastBufferWriter.GetWriteSize(Range)
-            ))
-            {
-                throw new OverflowException($"Not enough space to deserialize {nameof(SnapshotDataMessage)}");
-            }
-            reader.ReadValue(out CurrentTick);
-            reader.ReadValue(out Sequence);
-
-            reader.ReadValue(out Range);
-            ReceiveMainBuffer = new NativeArray<byte>(Range, Allocator.Temp);
-            reader.ReadBytesSafe((byte*)ReceiveMainBuffer.GetUnsafePtr(), Range);
-            reader.ReadValueSafe(out Ack);
-
-            reader.ReadValueSafe(out ushort length);
-            Entries = new NativeList<EntryData>(length, Allocator.Temp) { Length = length };
-            reader.ReadBytesSafe((byte*)Entries.GetUnsafePtr(), Entries.Length * sizeof(EntryData));
-
-            reader.ReadValueSafe(out length);
-            Spawns = new NativeList<SpawnData>(length, Allocator.Temp) { Length = length };
-            reader.ReadBytesSafe((byte*)Spawns.GetUnsafePtr(), Spawns.Length * sizeof(SpawnData));
-
-            reader.ReadValueSafe(out length);
-            Despawns = new NativeList<DespawnData>(length, Allocator.Temp) { Length = length };
-            reader.ReadBytesSafe((byte*)Despawns.GetUnsafePtr(), Despawns.Length * sizeof(DespawnData));
-
-            return true;
-        }
-
-        public void Handle(ref NetworkContext context)
-        {
-            using (ReceiveMainBuffer)
-            using (Entries)
-            using (Spawns)
-            using (Despawns)
-            {
-                var systemOwner = context.SystemOwner;
-                var senderId = context.SenderId;
-                if (systemOwner is NetworkManager networkManager)
-                {
-                    // todo: temporary hack around bug
-                    if (!networkManager.IsServer)
-                    {
-                        senderId = networkManager.ServerClientId;
-                    }
-
-                    var snapshotSystem = networkManager.SnapshotSystem;
-                    snapshotSystem.HandleSnapshot(senderId, this);
-                }
-                else
-                {
-                    var ownerData = (Tuple<SnapshotSystem, ulong>)systemOwner;
-                    var snapshotSystem = ownerData.Item1;
-                    snapshotSystem.HandleSnapshot(ownerData.Item2, this);
-                }
-            }
-        }
-    }
-}

Runtime/Messaging/Messages/SnapshotDataMessage.cs.meta

@@ -1,11 +0,0 @@
-fileFormatVersion: 2
-guid: 5cf75026c2ab86646aac16b39d7259ad
-MonoImporter:
-  externalObjects: {}
-  serializedVersion: 2
-  defaultReferences: []
-  executionOrder: 0
-  icon: {instanceID: 0}
-  userData: 
-  assetBundleName: 
-  assetBundleVariant: 

Runtime/Messaging/MessagingSystem.cs

@@ -67,7 +67,7 @@ namespace Unity.Netcode
         }
 
         public const int NON_FRAGMENTED_MESSAGE_MAX_SIZE = 1300;
-        public const int FRAGMENTED_MESSAGE_MAX_SIZE = int.MaxValue;
+        public const int FRAGMENTED_MESSAGE_MAX_SIZE = BytePacker.BitPackedIntMax;
 
         internal struct MessageWithHandler
         {

Runtime/Metrics/INetworkMetrics.cs

@@ -87,7 +87,13 @@ namespace Unity.Netcode
 
         void TrackPacketReceived(uint packetCount);
 
-        void TrackRttToServer(int rtt);
+        void UpdateRttToServer(int rtt);
+
+        void UpdateNetworkObjectsCount(int count);
+
+        void UpdateConnectionsCount(int count);
+
+        void UpdatePacketLoss(float packetLoss);
 
         void DispatchFrame();
     }

Runtime/Metrics/NetworkMetrics.cs

@@ -66,7 +66,7 @@ namespace Unity.Netcode
         private readonly EventMetric<SceneEventMetric> m_SceneEventSentEvent = new EventMetric<SceneEventMetric>(NetworkMetricTypes.SceneEventSent.Id);
         private readonly EventMetric<SceneEventMetric> m_SceneEventReceivedEvent = new EventMetric<SceneEventMetric>(NetworkMetricTypes.SceneEventReceived.Id);
 
-#if MULTIPLAYER_TOOLS_1_0_0_PRE_4
+#if MULTIPLAYER_TOOLS_1_0_0_PRE_7
         private readonly Counter m_PacketSentCounter = new Counter(NetworkMetricTypes.PacketsSent.Id)
         {
             ShouldResetOnDispatch = true,
@@ -79,6 +79,15 @@ namespace Unity.Netcode
         {
             ShouldResetOnDispatch = true,
         };
+        private readonly Gauge m_NetworkObjectsGauge = new Gauge(NetworkMetricTypes.NetworkObjects.Id)
+        {
+            ShouldResetOnDispatch = true,
+        };
+        private readonly Gauge m_ConnectionsGauge = new Gauge(NetworkMetricTypes.ConnectedClients.Id)
+        {
+            ShouldResetOnDispatch = true,
+        };
+        private readonly Gauge m_PacketLossGauge = new Gauge(NetworkMetricTypes.PacketLoss.Id);
 #endif
 
         private ulong m_NumberOfMetricsThisFrame;
@@ -97,9 +106,12 @@ namespace Unity.Netcode
                 .WithMetricEvents(m_RpcSentEvent, m_RpcReceivedEvent)
                 .WithMetricEvents(m_ServerLogSentEvent, m_ServerLogReceivedEvent)
                 .WithMetricEvents(m_SceneEventSentEvent, m_SceneEventReceivedEvent)
-#if MULTIPLAYER_TOOLS_1_0_0_PRE_4
+#if MULTIPLAYER_TOOLS_1_0_0_PRE_7
                 .WithCounters(m_PacketSentCounter, m_PacketReceivedCounter)
                 .WithGauges(m_RttToServerGauge)
+                .WithGauges(m_NetworkObjectsGauge)
+                .WithGauges(m_ConnectionsGauge)
+                .WithGauges(m_PacketLossGauge)
 #endif
                 .Build();
 
@@ -428,7 +440,7 @@ namespace Unity.Netcode
 
         public void TrackPacketSent(uint packetCount)
         {
-#if MULTIPLAYER_TOOLS_1_0_0_PRE_4
+#if MULTIPLAYER_TOOLS_1_0_0_PRE_7
             if (!CanSendMetrics)
             {
                 return;
@@ -441,7 +453,7 @@ namespace Unity.Netcode
 
         public void TrackPacketReceived(uint packetCount)
         {
-#if MULTIPLAYER_TOOLS_1_0_0_PRE_4
+#if MULTIPLAYER_TOOLS_1_0_0_PRE_7
             if (!CanSendMetrics)
             {
                 return;
@@ -452,15 +464,51 @@ namespace Unity.Netcode
 #endif
         }
 
-        public void TrackRttToServer(int rtt)
+        public void UpdateRttToServer(int rttMilliseconds)
         {
-#if MULTIPLAYER_TOOLS_1_0_0_PRE_4
+#if MULTIPLAYER_TOOLS_1_0_0_PRE_7
+            if (!CanSendMetrics)
+            {
+                return;
+            }
+            var rttSeconds = rttMilliseconds * 1e-3;
+            m_RttToServerGauge.Set(rttSeconds);
+#endif
+        }
+
+        public void UpdateNetworkObjectsCount(int count)
+        {
+#if MULTIPLAYER_TOOLS_1_0_0_PRE_7
             if (!CanSendMetrics)
             {
                 return;
             }
 
-            m_RttToServerGauge.Set(rtt);
+            m_NetworkObjectsGauge.Set(count);
+#endif
+        }
+
+        public void UpdateConnectionsCount(int count)
+        {
+#if MULTIPLAYER_TOOLS_1_0_0_PRE_7
+            if (!CanSendMetrics)
+            {
+                return;
+            }
+
+            m_ConnectionsGauge.Set(count);
+#endif
+        }
+
+        public void UpdatePacketLoss(float packetLoss)
+        {
+#if MULTIPLAYER_TOOLS_1_0_0_PRE_7
+            if (!CanSendMetrics)
+            {
+                return;
+            }
+
+            m_PacketLossGauge.Set(packetLoss);
 #endif
         }
 

Runtime/Metrics/NullNetworkMetrics.cs

@@ -145,7 +145,19 @@ namespace Unity.Netcode
         {
         }
 
-        public void TrackRttToServer(int rtt)
+        public void UpdateRttToServer(int rtt)
+        {
+        }
+
+        public void UpdateNetworkObjectsCount(int count)
+        {
+        }
+
+        public void UpdateConnectionsCount(int count)
+        {
+        }
+
+        public void UpdatePacketLoss(float packetLoss)
         {
         }
 

Runtime/NetworkVariable/Collections/NetworkList.cs

@@ -24,17 +24,12 @@ namespace Unity.Netcode
         /// </summary>
         public event OnListChangedDelegate OnListChanged;
 
-        /// <summary>
-        /// Creates a NetworkList with the default value and settings
-        /// </summary>
         public NetworkList() { }
 
-        /// <summary>
-        /// Creates a NetworkList with the default value and custom settings
-        /// </summary>
-        /// <param name="readPerm">The read permission to use for the NetworkList</param>
-        /// <param name="values">The initial value to use for the NetworkList</param>
-        public NetworkList(NetworkVariableReadPermission readPerm, IEnumerable<T> values) : base(readPerm)
+        public NetworkList(IEnumerable<T> values = default,
+            NetworkVariableReadPermission readPerm = DefaultReadPerm,
+            NetworkVariableWritePermission writePerm = DefaultWritePerm)
+            : base(readPerm, writePerm)
         {
             foreach (var value in values)
             {
@@ -42,19 +37,6 @@ namespace Unity.Netcode
             }
         }
 
-        /// <summary>
-        /// Creates a NetworkList with a custom value and the default settings
-        /// </summary>
-        /// <param name="values">The initial value to use for the NetworkList</param>
-        public NetworkList(IEnumerable<T> values)
-        {
-            foreach (var value in values)
-            {
-                m_List.Add(value);
-
-            }
-        }
-
         /// <inheritdoc />
         public override void ResetDirty()
         {

Runtime/NetworkVariable/NetworkVariable.cs

@@ -1,5 +1,7 @@
 using UnityEngine;
 using System;
+using System.Runtime.CompilerServices;
+using Unity.Collections.LowLevel.Unsafe;
 
 namespace Unity.Netcode
 {
@@ -22,7 +24,8 @@ namespace Unity.Netcode
         }
 
         // Functions that serialize other types
-        private static void WriteValue<TForMethod>(FastBufferWriter writer, in TForMethod value) where TForMethod : unmanaged
+        private static void WriteValue<TForMethod>(FastBufferWriter writer, in TForMethod value)
+            where TForMethod : unmanaged
         {
             writer.WriteValueSafe(value);
         }
@@ -37,16 +40,13 @@ namespace Unity.Netcode
 
         internal delegate void ReadDelegate<TForMethod>(FastBufferReader reader, out TForMethod value);
 
-        // These static delegates provide the right implementation for writing and reading a particular network variable
-        // type.
-        //
+        // These static delegates provide the right implementation for writing and reading a particular network variable type.
         // For most types, these default to WriteValue() and ReadValue(), which perform simple memcpy operations.
         //
         // INetworkSerializableILPP will generate startup code that will set it to WriteNetworkSerializable()
         // and ReadNetworkSerializable() for INetworkSerializable types, which will call NetworkSerialize().
         //
-        // In the future we may be able to use this to provide packing implementations for floats and integers to
-        // optimize bandwidth usage.
+        // In the future we may be able to use this to provide packing implementations for floats and integers to optimize bandwidth usage.
         //
         // The reason this is done is to avoid runtime reflection and boxing in NetworkVariable - without this,
         // NetworkVariable would need to do a `var is INetworkSerializable` check, and then cast to INetworkSerializable,
@@ -69,38 +69,11 @@ namespace Unity.Netcode
         /// </summary>
         public OnValueChangedDelegate OnValueChanged;
 
-        /// <summary>
-        /// Creates a NetworkVariable with the default value and custom read permission
-        /// </summary>
-        /// <param name="readPerm">The read permission for the NetworkVariable</param>
 
-        public NetworkVariable()
-        {
-        }
-
-        /// <summary>
-        /// Creates a NetworkVariable with the default value and custom read permission
-        /// </summary>
-        /// <param name="readPerm">The read permission for the NetworkVariable</param>
-        public NetworkVariable(NetworkVariableReadPermission readPerm) : base(readPerm)
-        {
-        }
-
-        /// <summary>
-        /// Creates a NetworkVariable with a custom value and custom settings
-        /// </summary>
-        /// <param name="readPerm">The read permission for the NetworkVariable</param>
-        /// <param name="value">The initial value to use for the NetworkVariable</param>
-        public NetworkVariable(NetworkVariableReadPermission readPerm, T value) : base(readPerm)
-        {
-            m_InternalValue = value;
-        }
-
-        /// <summary>
-        /// Creates a NetworkVariable with a custom value and the default read permission
-        /// </summary>
-        /// <param name="value">The initial value to use for the NetworkVariable</param>
-        public NetworkVariable(T value)
+        public NetworkVariable(T value = default,
+            NetworkVariableReadPermission readPerm = DefaultReadPerm,
+            NetworkVariableWritePermission writePerm = DefaultWritePerm)
+            : base(readPerm, writePerm)
         {
             m_InternalValue = value;
         }
@@ -116,19 +89,36 @@ namespace Unity.Netcode
             get => m_InternalValue;
             set
             {
-                // this could be improved. The Networking Manager is not always initialized here
-                //  Good place to decouple network manager from the network variable
-
-                // Also, note this is not really very water-tight, if you are running as a host
-                //  we cannot tell if a NetworkVariable write is happening inside client-ish code
-                if (m_NetworkBehaviour && (m_NetworkBehaviour.NetworkManager.IsClient && !m_NetworkBehaviour.NetworkManager.IsHost))
+                // Compare bitwise
+                if (ValueEquals(ref m_InternalValue, ref value))
                 {
-                    throw new InvalidOperationException("Client can't write to NetworkVariables");
+                    return;
                 }
+
+                if (m_NetworkBehaviour && !CanClientWrite(m_NetworkBehaviour.NetworkManager.LocalClientId))
+                {
+                    throw new InvalidOperationException("Client is not allowed to write to this NetworkVariable");
+                }
+
                 Set(value);
             }
         }
 
+        // Compares two values of the same unmanaged type by underlying memory
+        // Ignoring any overriden value checks
+        // Size is fixed
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        private static unsafe bool ValueEquals(ref T a, ref T b)
+        {
+            // get unmanaged pointers
+            var aptr = UnsafeUtility.AddressOf(ref a);
+            var bptr = UnsafeUtility.AddressOf(ref b);
+
+            // compare addresses
+            return UnsafeUtility.MemCmp(aptr, bptr, sizeof(T)) == 0;
+        }
+
+
         private protected void Set(T value)
         {
             m_IsDirty = true;
@@ -146,7 +136,6 @@ namespace Unity.Netcode
             WriteField(writer);
         }
 
-
         /// <summary>
         /// Reads value from the reader and applies it
         /// </summary>

Runtime/NetworkVariable/NetworkVariableBase.cs

@@ -19,9 +19,15 @@ namespace Unity.Netcode
             m_NetworkBehaviour = networkBehaviour;
         }
 
-        protected NetworkVariableBase(NetworkVariableReadPermission readPermIn = NetworkVariableReadPermission.Everyone)
+        public const NetworkVariableReadPermission DefaultReadPerm = NetworkVariableReadPermission.Everyone;
+        public const NetworkVariableWritePermission DefaultWritePerm = NetworkVariableWritePermission.Server;
+
+        protected NetworkVariableBase(
+            NetworkVariableReadPermission readPerm = DefaultReadPerm,
+            NetworkVariableWritePermission writePerm = DefaultWritePerm)
         {
-            ReadPerm = readPermIn;
+            ReadPerm = readPerm;
+            WritePerm = writePerm;
         }
 
         private protected bool m_IsDirty;
@@ -37,6 +43,8 @@ namespace Unity.Netcode
         /// </summary>
         public readonly NetworkVariableReadPermission ReadPerm;
 
+        public readonly NetworkVariableWritePermission WritePerm;
+
         /// <summary>
         /// Sets whether or not the variable needs to be delta synced
         /// </summary>
@@ -62,26 +70,28 @@ namespace Unity.Netcode
             return m_IsDirty;
         }
 
-        public virtual bool ShouldWrite(ulong clientId, bool isServer)
-        {
-            return IsDirty() && isServer && CanClientRead(clientId);
-        }
-
-        /// <summary>
-        /// Gets Whether or not a specific client can read to the varaible
-        /// </summary>
-        /// <param name="clientId">The clientId of the remote client</param>
-        /// <returns>Whether or not the client can read to the variable</returns>
         public bool CanClientRead(ulong clientId)
         {
             switch (ReadPerm)
             {
+                default:
                 case NetworkVariableReadPermission.Everyone:
                     return true;
-                case NetworkVariableReadPermission.OwnerOnly:
-                    return m_NetworkBehaviour.OwnerClientId == clientId;
+                case NetworkVariableReadPermission.Owner:
+                    return clientId == m_NetworkBehaviour.NetworkObject.OwnerClientId;
+            }
+        }
+
+        public bool CanClientWrite(ulong clientId)
+        {
+            switch (WritePerm)
+            {
+                default:
+                case NetworkVariableWritePermission.Server:
+                    return clientId == NetworkManager.ServerClientId;
+                case NetworkVariableWritePermission.Owner:
+                    return clientId == m_NetworkBehaviour.NetworkObject.OwnerClientId;
             }
-            return true;
         }
 
         /// <summary>
@@ -107,7 +117,6 @@ namespace Unity.Netcode
         /// </summary>
         /// <param name="reader">The stream to read the delta from</param>
         /// <param name="keepDirtyDelta">Whether or not the delta should be kept as dirty or consumed</param>
-
         public abstract void ReadDelta(FastBufferReader reader, bool keepDirtyDelta);
 
         public virtual void Dispose()

Runtime/NetworkVariable/NetworkVariablePermission.cs

@@ -1,18 +1,14 @@
 namespace Unity.Netcode
 {
-    /// <summary>
-    /// Permission type
-    /// </summary>
     public enum NetworkVariableReadPermission
     {
-        /// <summary>
-        /// Everyone
-        /// </summary>
         Everyone,
+        Owner,
+    }
 
-        /// <summary>
-        /// Owner-ownly
-        /// </summary>
-        OwnerOnly,
+    public enum NetworkVariableWritePermission
+    {
+        Server,
+        Owner
     }
 }

Runtime/SceneManagement/NetworkSceneManager.cs

@@ -132,7 +132,7 @@ namespace Unity.Netcode
         private const NetworkDelivery k_DeliveryType = NetworkDelivery.ReliableFragmentedSequenced;
         internal const int InvalidSceneNameOrPath = -1;
 
-        // Used to be able to turn re-synchronization off for future snapshot development purposes.
+        // Used to be able to turn re-synchronization off
         internal static bool DisableReSynchronization;
 
         /// <summary>
@@ -488,9 +488,19 @@ namespace Unity.Netcode
                 var scenePath = SceneUtility.GetScenePathByBuildIndex(i);
                 var hash = XXHash.Hash32(scenePath);
                 var buildIndex = SceneUtility.GetBuildIndexByScenePath(scenePath);
+
+                // In the rare-case scenario where a programmatically generated build has duplicate
+                // scene entries, we will log an error and skip the entry
+                if (!HashToBuildIndex.ContainsKey(hash))
+                {
                     HashToBuildIndex.Add(hash, buildIndex);
                     BuildIndexToHash.Add(buildIndex, hash);
                 }
+                else
+                {
+                    Debug.LogError($"{nameof(NetworkSceneManager)} is skipping duplicate scene path entry {scenePath}. Make sure your scenes in build list does not contain duplicates!");
+                }
+            }
         }
 
         /// <summary>
@@ -520,7 +530,8 @@ namespace Unity.Netcode
             }
             else
             {
-                throw new Exception($"Scene Hash {sceneHash} does not exist in the {nameof(HashToBuildIndex)} table!");
+                throw new Exception($"Scene Hash {sceneHash} does not exist in the {nameof(HashToBuildIndex)} table!  Verify that all scenes requiring" +
+                    $" server to client synchronization are in the scenes in build list.");
             }
         }
 
@@ -876,7 +887,7 @@ namespace Unity.Netcode
             {
                 SceneEventType = sceneEventProgress.SceneEventType,
                 SceneName = SceneNameFromHash(sceneEventProgress.SceneHash),
-                ClientId = m_NetworkManager.ServerClientId,
+                ClientId = NetworkManager.ServerClientId,
                 LoadSceneMode = sceneEventProgress.LoadSceneMode,
                 ClientsThatCompleted = sceneEventProgress.DoneClients,
                 ClientsThatTimedOut = m_NetworkManager.ConnectedClients.Keys.Except(sceneEventProgress.DoneClients).ToList(),
@@ -947,10 +958,10 @@ namespace Unity.Netcode
                 SceneEventType = sceneEventData.SceneEventType,
                 LoadSceneMode = sceneEventData.LoadSceneMode,
                 SceneName = sceneName,
-                ClientId = m_NetworkManager.ServerClientId  // Server can only invoke this
+                ClientId = NetworkManager.ServerClientId  // Server can only invoke this
             });
 
-            OnUnload?.Invoke(m_NetworkManager.ServerClientId, sceneName, sceneUnload);
+            OnUnload?.Invoke(NetworkManager.ServerClientId, sceneName, sceneUnload);
 
             //Return the status
             return sceneEventProgress.Status;
@@ -1017,12 +1028,12 @@ namespace Unity.Netcode
                 // Server sends the unload scene notification after unloading because it will despawn all scene relative in-scene NetworkObjects
                 // If we send this event to all clients before the server is finished unloading they will get warning about an object being
                 // despawned that no longer exists
-                SendSceneEventData(sceneEventId, m_NetworkManager.ConnectedClientsIds.Where(c => c != m_NetworkManager.ServerClientId).ToArray());
+                SendSceneEventData(sceneEventId, m_NetworkManager.ConnectedClientsIds.Where(c => c != NetworkManager.ServerClientId).ToArray());
 
                 //Only if we are a host do we want register having loaded for the associated SceneEventProgress
                 if (SceneEventProgressTracking.ContainsKey(sceneEventData.SceneEventProgressId) && m_NetworkManager.IsHost)
                 {
-                    SceneEventProgressTracking[sceneEventData.SceneEventProgressId].AddClientAsDone(m_NetworkManager.ServerClientId);
+                    SceneEventProgressTracking[sceneEventData.SceneEventProgressId].AddClientAsDone(NetworkManager.ServerClientId);
                 }
             }
 
@@ -1035,7 +1046,7 @@ namespace Unity.Netcode
                 SceneEventType = sceneEventData.SceneEventType,
                 LoadSceneMode = sceneEventData.LoadSceneMode,
                 SceneName = SceneNameFromHash(sceneEventData.SceneHash),
-                ClientId = m_NetworkManager.IsServer ? m_NetworkManager.ServerClientId : m_NetworkManager.LocalClientId
+                ClientId = m_NetworkManager.IsServer ? NetworkManager.ServerClientId : m_NetworkManager.LocalClientId
             });
 
             OnUnloadComplete?.Invoke(m_NetworkManager.LocalClientId, SceneNameFromHash(sceneEventData.SceneHash));
@@ -1043,7 +1054,7 @@ namespace Unity.Netcode
             // Clients send a notification back to the server they have completed the unload scene event
             if (!m_NetworkManager.IsServer)
             {
-                SendSceneEventData(sceneEventId, new ulong[] { m_NetworkManager.ServerClientId });
+                SendSceneEventData(sceneEventId, new ulong[] { NetworkManager.ServerClientId });
             }
 
             EndSceneEvent(sceneEventId);
@@ -1079,7 +1090,7 @@ namespace Unity.Netcode
                         SceneEventType = SceneEventType.Unload,
                         SceneName = keyHandleEntry.Value.name,
                         LoadSceneMode = LoadSceneMode.Additive, // The only scenes unloaded are scenes that were additively loaded
-                        ClientId = m_NetworkManager.ServerClientId
+                        ClientId = NetworkManager.ServerClientId
                     });
                 }
             }
@@ -1147,10 +1158,10 @@ namespace Unity.Netcode
                 SceneEventType = sceneEventData.SceneEventType,
                 LoadSceneMode = sceneEventData.LoadSceneMode,
                 SceneName = sceneName,
-                ClientId = m_NetworkManager.ServerClientId
+                ClientId = NetworkManager.ServerClientId
             });
 
-            OnLoad?.Invoke(m_NetworkManager.ServerClientId, sceneName, sceneEventData.LoadSceneMode, sceneLoad);
+            OnLoad?.Invoke(NetworkManager.ServerClientId, sceneName, sceneEventData.LoadSceneMode, sceneLoad);
 
             //Return our scene progress instance
             return sceneEventProgress.Status;
@@ -1187,7 +1198,6 @@ namespace Unity.Netcode
             // When it is set: Just before starting the asynchronous loading call
             // When it is unset: After the scene has loaded, the PopulateScenePlacedObjects is called, and all NetworkObjects in the do
             // not destroy temporary scene are moved into the active scene
-            // TODO: When Snapshot scene spawning is enabled this needs to be removed.
             if (sceneEventData.LoadSceneMode == LoadSceneMode.Single)
             {
                 IsSpawnedObjectsPendingInDontDestroyOnLoad = true;
@@ -1278,7 +1288,9 @@ namespace Unity.Netcode
                 {
                     if (!keyValuePairBySceneHandle.Value.IsPlayerObject)
                     {
-                        m_NetworkManager.SpawnManager.SpawnNetworkObjectLocally(keyValuePairBySceneHandle.Value, m_NetworkManager.SpawnManager.GetNetworkObjectId(), true, false, null, true);
+                        // All in-scene placed NetworkObjects default to being owned by the server
+                        m_NetworkManager.SpawnManager.SpawnNetworkObjectLocally(keyValuePairBySceneHandle.Value,
+                            m_NetworkManager.SpawnManager.GetNetworkObjectId(), true, false, NetworkManager.ServerClientId, true);
                     }
                 }
             }
@@ -1290,7 +1302,7 @@ namespace Unity.Netcode
             for (int j = 0; j < m_NetworkManager.ConnectedClientsList.Count; j++)
             {
                 var clientId = m_NetworkManager.ConnectedClientsList[j].ClientId;
-                if (clientId != m_NetworkManager.ServerClientId)
+                if (clientId != NetworkManager.ServerClientId)
                 {
                     sceneEventData.TargetClientId = clientId;
                     var message = new SceneEventMessage
@@ -1309,16 +1321,16 @@ namespace Unity.Netcode
                 SceneEventType = SceneEventType.LoadComplete,
                 LoadSceneMode = sceneEventData.LoadSceneMode,
                 SceneName = SceneNameFromHash(sceneEventData.SceneHash),
-                ClientId = m_NetworkManager.ServerClientId,
+                ClientId = NetworkManager.ServerClientId,
                 Scene = scene,
             });
 
-            OnLoadComplete?.Invoke(m_NetworkManager.ServerClientId, SceneNameFromHash(sceneEventData.SceneHash), sceneEventData.LoadSceneMode);
+            OnLoadComplete?.Invoke(NetworkManager.ServerClientId, SceneNameFromHash(sceneEventData.SceneHash), sceneEventData.LoadSceneMode);
 
             //Second, only if we are a host do we want register having loaded for the associated SceneEventProgress
             if (SceneEventProgressTracking.ContainsKey(sceneEventData.SceneEventProgressId) && m_NetworkManager.IsHost)
             {
-                SceneEventProgressTracking[sceneEventData.SceneEventProgressId].AddClientAsDone(m_NetworkManager.ServerClientId);
+                SceneEventProgressTracking[sceneEventData.SceneEventProgressId].AddClientAsDone(NetworkManager.ServerClientId);
             }
             EndSceneEvent(sceneEventId);
         }
@@ -1333,7 +1345,7 @@ namespace Unity.Netcode
             sceneEventData.DeserializeScenePlacedObjects();
 
             sceneEventData.SceneEventType = SceneEventType.LoadComplete;
-            SendSceneEventData(sceneEventId, new ulong[] { m_NetworkManager.ServerClientId });
+            SendSceneEventData(sceneEventId, new ulong[] { NetworkManager.ServerClientId });
             m_IsSceneEventActive = false;
 
             // Notify local client that the scene was loaded
@@ -1544,9 +1556,9 @@ namespace Unity.Netcode
             {
                 EventData = responseSceneEventData
             };
-            var size = m_NetworkManager.SendMessage(ref message, k_DeliveryType, m_NetworkManager.ServerClientId);
+            var size = m_NetworkManager.SendMessage(ref message, k_DeliveryType, NetworkManager.ServerClientId);
 
-            m_NetworkManager.NetworkMetrics.TrackSceneEventSent(m_NetworkManager.ServerClientId, (uint)responseSceneEventData.SceneEventType, sceneName, size);
+            m_NetworkManager.NetworkMetrics.TrackSceneEventSent(NetworkManager.ServerClientId, (uint)responseSceneEventData.SceneEventType, sceneName, size);
 
             EndSceneEvent(responseSceneEventData.SceneEventId);
 
@@ -1600,7 +1612,7 @@ namespace Unity.Netcode
                             sceneEventData.SynchronizeSceneNetworkObjects(m_NetworkManager);
 
                             sceneEventData.SceneEventType = SceneEventType.SynchronizeComplete;
-                            SendSceneEventData(sceneEventId, new ulong[] { m_NetworkManager.ServerClientId });
+                            SendSceneEventData(sceneEventId, new ulong[] { NetworkManager.ServerClientId });
 
                             // All scenes are synchronized, let the server know we are done synchronizing
                             m_NetworkManager.IsConnectedClient = true;
@@ -1627,7 +1639,7 @@ namespace Unity.Netcode
                         OnSceneEvent?.Invoke(new SceneEvent()
                         {
                             SceneEventType = sceneEventData.SceneEventType,
-                            ClientId = m_NetworkManager.ServerClientId,  // Server sent this to client
+                            ClientId = NetworkManager.ServerClientId,  // Server sent this to client
                         });
 
                         EndSceneEvent(sceneEventId);
@@ -1642,7 +1654,7 @@ namespace Unity.Netcode
                             SceneEventType = sceneEventData.SceneEventType,
                             LoadSceneMode = sceneEventData.LoadSceneMode,
                             SceneName = SceneNameFromHash(sceneEventData.SceneHash),
-                            ClientId = m_NetworkManager.ServerClientId,
+                            ClientId = NetworkManager.ServerClientId,
                             ClientsThatCompleted = sceneEventData.ClientsCompleted,
                             ClientsThatTimedOut = sceneEventData.ClientsTimedOut,
                         });
@@ -1734,8 +1746,6 @@ namespace Unity.Netcode
                         // NetworkObjects
                         m_NetworkManager.InvokeOnClientConnectedCallback(clientId);
 
-                        // TODO: This check and associated code can be removed once we determine all
-                        // snapshot destroy messages are being updated until the server receives ACKs
                         if (sceneEventData.ClientNeedsReSynchronization() && !DisableReSynchronization)
                         {
                             sceneEventData.SceneEventType = SceneEventType.ReSynchronize;
@@ -1830,7 +1840,7 @@ namespace Unity.Netcode
         /// Using the local scene relative Scene.handle as a sub-key to the root dictionary allows us to
         /// distinguish between duplicate in-scene placed NetworkObjects
         /// </summary>
-        private void PopulateScenePlacedObjects(Scene sceneToFilterBy, bool clearScenePlacedObjects = true)
+        internal void PopulateScenePlacedObjects(Scene sceneToFilterBy, bool clearScenePlacedObjects = true)
         {
             if (clearScenePlacedObjects)
             {
@@ -1845,25 +1855,26 @@ namespace Unity.Netcode
             // at the end of scene loading we use this list to soft synchronize all in-scene placed NetworkObjects
             foreach (var networkObjectInstance in networkObjects)
             {
-                // We check to make sure the NetworkManager instance is the same one to be "NetcodeIntegrationTestHelpers" compatible and filter the list on a per scene basis (additive scenes)
-                if (networkObjectInstance.IsSceneObject == null && networkObjectInstance.NetworkManager == m_NetworkManager && networkObjectInstance.gameObject.scene == sceneToFilterBy &&
-                    networkObjectInstance.gameObject.scene.handle == sceneToFilterBy.handle)
+                var globalObjectIdHash = networkObjectInstance.GlobalObjectIdHash;
+                var sceneHandle = networkObjectInstance.gameObject.scene.handle;
+                // We check to make sure the NetworkManager instance is the same one to be "NetcodeIntegrationTestHelpers" compatible and filter the list on a per scene basis (for additive scenes)
+                if (networkObjectInstance.IsSceneObject != false && networkObjectInstance.NetworkManager == m_NetworkManager && networkObjectInstance.gameObject.scene == sceneToFilterBy &&
+                    sceneHandle == sceneToFilterBy.handle)
                 {
-                    if (!ScenePlacedObjects.ContainsKey(networkObjectInstance.GlobalObjectIdHash))
+                    if (!ScenePlacedObjects.ContainsKey(globalObjectIdHash))
                     {
-                        ScenePlacedObjects.Add(networkObjectInstance.GlobalObjectIdHash, new Dictionary<int, NetworkObject>());
+                        ScenePlacedObjects.Add(globalObjectIdHash, new Dictionary<int, NetworkObject>());
                     }
 
-                    if (!ScenePlacedObjects[networkObjectInstance.GlobalObjectIdHash].ContainsKey(networkObjectInstance.gameObject.scene.handle))
+                    if (!ScenePlacedObjects[globalObjectIdHash].ContainsKey(sceneHandle))
                     {
-                        ScenePlacedObjects[networkObjectInstance.GlobalObjectIdHash].Add(networkObjectInstance.gameObject.scene.handle, networkObjectInstance);
+                        ScenePlacedObjects[globalObjectIdHash].Add(sceneHandle, networkObjectInstance);
                     }
                     else
                     {
-                        var exitingEntryName = ScenePlacedObjects[networkObjectInstance.GlobalObjectIdHash][networkObjectInstance.gameObject.scene.handle] != null ?
-                            ScenePlacedObjects[networkObjectInstance.GlobalObjectIdHash][networkObjectInstance.gameObject.scene.handle].name : "Null Entry";
+                        var exitingEntryName = ScenePlacedObjects[globalObjectIdHash][sceneHandle] != null ? ScenePlacedObjects[globalObjectIdHash][sceneHandle].name : "Null Entry";
                         throw new Exception($"{networkObjectInstance.name} tried to registered with {nameof(ScenePlacedObjects)} which already contains " +
-                            $"the same {nameof(NetworkObject.GlobalObjectIdHash)} value {networkObjectInstance.GlobalObjectIdHash} for {exitingEntryName}!");
+                            $"the same {nameof(NetworkObject.GlobalObjectIdHash)} value {globalObjectIdHash} for {exitingEntryName}!");
                     }
                 }
             }

Runtime/SceneManagement/SceneEventData.cs

@@ -41,7 +41,6 @@ namespace Unity.Netcode
         /// <b>Invocation:</b> Server Side<br/>
         /// <b>Message Flow:</b> Server to client<br/>
         /// <b>Event Notification:</b> Both server and client receive a local notification<br/>
-        /// <em>Note: This will be removed once snapshot and buffered messages are finalized as it will no longer be needed at that point.</em>
         /// </summary>
         ReSynchronize,
         /// <summary>
@@ -592,9 +591,6 @@ namespace Unity.Netcode
                         networkObject.IsSpawned = false;
                         if (m_NetworkManager.PrefabHandler.ContainsHandler(networkObject))
                         {
-                            // Since this is the client side and we have missed the delete message, until the Snapshot system is in place for spawn and despawn handling
-                            // we have to remove this from the list of spawned objects manually or when a NetworkObjectId is recycled the client will throw an error
-                            // about the id already being assigned.
                             if (m_NetworkManager.SpawnManager.SpawnedObjects.ContainsKey(networkObjectId))
                             {
                                 m_NetworkManager.SpawnManager.SpawnedObjects.Remove(networkObjectId);

Runtime/Serialization/BytePacker.cs

@@ -281,6 +281,17 @@ namespace Unity.Netcode
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void WriteValueBitPacked<T>(FastBufferWriter writer, T value) where T: unmanaged => writer.WriteValueSafe(value);
 #else
+
+        public const ushort BitPackedUshortMax = (1 << 15) - 1;
+        public const short BitPackedShortMax = (1 << 14) - 1;
+        public const short BitPackedShortMin = -(1 << 14);
+        public const uint BitPackedUintMax = (1 << 30) - 1;
+        public const int BitPackedIntMax = (1 << 29) - 1;
+        public const int BitPackedIntMin = -(1 << 29);
+        public const ulong BitPackedULongMax = (1L << 61) - 1;
+        public const long BitPackedLongMax = (1L << 60) - 1;
+        public const long BitPackedLongMin = -(1L << 60);
+
         /// <summary>
         /// Writes a 14-bit signed short to the buffer in a bit-encoded packed format.
         /// The first bit indicates whether the value is 1 byte or 2.
@@ -307,7 +318,7 @@ namespace Unity.Netcode
         public static void WriteValueBitPacked(FastBufferWriter writer, ushort value)
         {
 #if DEVELOPMENT_BUILD || UNITY_EDITOR
-            if (value >= 0b1000_0000_0000_0000)
+            if (value >= BitPackedUshortMax)
             {
                 throw new ArgumentException("BitPacked ushorts must be <= 15 bits");
             }
@@ -356,7 +367,7 @@ namespace Unity.Netcode
         public static void WriteValueBitPacked(FastBufferWriter writer, uint value)
         {
 #if DEVELOPMENT_BUILD || UNITY_EDITOR
-            if (value >= 0b0100_0000_0000_0000_0000_0000_0000_0000)
+            if (value > BitPackedUintMax)
             {
                 throw new ArgumentException("BitPacked uints must be <= 30 bits");
             }
@@ -396,7 +407,7 @@ namespace Unity.Netcode
         public static void WriteValueBitPacked(FastBufferWriter writer, ulong value)
         {
 #if DEVELOPMENT_BUILD || UNITY_EDITOR
-            if (value >= 0b0010_0000_0000_0000_0000_0000_0000_0000_0000_0000_0000_0000_0000_0000_0000_0000)
+            if (value > BitPackedULongMax)
             {
                 throw new ArgumentException("BitPacked ulongs must be <= 61 bits");
             }

Runtime/Serialization/FastBufferReader.cs

@@ -19,7 +19,7 @@ namespace Unity.Netcode
 #endif
         }
 
-        internal readonly unsafe ReaderHandle* Handle;
+        internal unsafe ReaderHandle* Handle;
 
         /// <summary>
         /// Get the current read position
@@ -39,6 +39,11 @@ namespace Unity.Netcode
             get => Handle->Length;
         }
 
+        /// <summary>
+        /// Gets a value indicating whether the reader has been initialized and a handle allocated.
+        /// </summary>
+        public unsafe bool IsInitialized => Handle != null;
+
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         internal unsafe void CommitBitwiseReads(int amount)
         {
@@ -196,6 +201,7 @@ namespace Unity.Netcode
         public unsafe void Dispose()
         {
             UnsafeUtility.Free(Handle, Handle->Allocator);
+            Handle = null;
         }
 
         /// <summary>

Runtime/Serialization/FastBufferWriter.cs

@@ -22,7 +22,7 @@ namespace Unity.Netcode
 #endif
         }
 
-        internal readonly unsafe WriterHandle* Handle;
+        internal unsafe WriterHandle* Handle;
 
         private static byte[] s_ByteArrayCache = new byte[65535];
 
@@ -62,6 +62,11 @@ namespace Unity.Netcode
             get => Handle->Position > Handle->Length ? Handle->Position : Handle->Length;
         }
 
+        /// <summary>
+        /// Gets a value indicating whether the writer has been initialized and a handle allocated.
+        /// </summary>
+        public unsafe bool IsInitialized => Handle != null;
+
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         internal unsafe void CommitBitwiseWrites(int amount)
@@ -111,6 +116,7 @@ namespace Unity.Netcode
                 UnsafeUtility.Free(Handle->BufferPointer, Handle->Allocator);
             }
             UnsafeUtility.Free(Handle, Handle->Allocator);
+            Handle = null;
         }
 
         /// <summary>

Runtime/Spawning/NetworkSpawnManager.cs

@@ -21,6 +21,122 @@ namespace Unity.Netcode
         /// </summary>
         public readonly HashSet<NetworkObject> SpawnedObjectsList = new HashSet<NetworkObject>();
 
+        /// <summary>
+        /// Use to get all NetworkObjects owned by a client
+        /// Ownership to Objects Table Format:
+        /// [ClientId][NetworkObjectId][NetworkObject]
+        /// Server: Keeps track of all clients' ownership
+        /// Client: Keeps track of only its ownership
+        /// </summary>
+        public readonly Dictionary<ulong, Dictionary<ulong, NetworkObject>> OwnershipToObjectsTable = new Dictionary<ulong, Dictionary<ulong, NetworkObject>>();
+
+        /// <summary>
+        /// Object to Ownership Table:
+        /// [NetworkObjectId][ClientId]
+        /// Used internally to find the client Id that currently owns
+        /// the NetworkObject
+        /// </summary>
+        private Dictionary<ulong, ulong> m_ObjectToOwnershipTable = new Dictionary<ulong, ulong>();
+
+        /// <summary>
+        /// Used to update a NetworkObject's ownership
+        /// </summary>
+        internal void UpdateOwnershipTable(NetworkObject networkObject, ulong newOwner, bool isRemoving = false)
+        {
+            var previousOwner = newOwner;
+
+            // Use internal lookup table to see if the NetworkObject has a previous owner
+            if (m_ObjectToOwnershipTable.ContainsKey(networkObject.NetworkObjectId))
+            {
+                // Keep track of the previous owner's ClientId
+                previousOwner = m_ObjectToOwnershipTable[networkObject.NetworkObjectId];
+
+                // We are either despawning (remove) or changing ownership (assign)
+                if (isRemoving)
+                {
+                    m_ObjectToOwnershipTable.Remove(networkObject.NetworkObjectId);
+                }
+                else
+                {
+                    m_ObjectToOwnershipTable[networkObject.NetworkObjectId] = newOwner;
+                }
+            }
+            else
+            {
+                // Otherwise, just add a new lookup entry
+                m_ObjectToOwnershipTable.Add(networkObject.NetworkObjectId, newOwner);
+            }
+
+            // Check to see if we had a previous owner
+            if (previousOwner != newOwner && OwnershipToObjectsTable.ContainsKey(previousOwner))
+            {
+                // Before updating the previous owner, assure this entry exists
+                if (OwnershipToObjectsTable[previousOwner].ContainsKey(networkObject.NetworkObjectId))
+                {
+                    // Remove the previous owner's entry
+                    OwnershipToObjectsTable[previousOwner].Remove(networkObject.NetworkObjectId);
+
+                    // Server or Host alway invokes the lost ownership notification locally
+                    if (NetworkManager.IsServer)
+                    {
+                        networkObject.InvokeBehaviourOnLostOwnership();
+                    }
+
+                    // If we are removing the entry (i.e. despawning or client lost ownership)
+                    if (isRemoving)
+                    {
+                        return;
+                    }
+                }
+                else
+                {
+                    // Really, as long as UpdateOwnershipTable is invoked when ownership is gained or lost this should never happen
+                    throw new Exception($"Client-ID {previousOwner} had a partial {nameof(m_ObjectToOwnershipTable)} entry! Potentially corrupted {nameof(OwnershipToObjectsTable)}?");
+                }
+            }
+
+            // If the owner doesn't have an entry then create one
+            if (!OwnershipToObjectsTable.ContainsKey(newOwner))
+            {
+                OwnershipToObjectsTable.Add(newOwner, new Dictionary<ulong, NetworkObject>());
+            }
+
+            // Sanity check to make sure we don't already have this entry (we shouldn't)
+            if (!OwnershipToObjectsTable[newOwner].ContainsKey(networkObject.NetworkObjectId))
+            {
+                // Add the new ownership entry
+                OwnershipToObjectsTable[newOwner].Add(networkObject.NetworkObjectId, networkObject);
+
+                // Server or Host always invokes the gained ownership notification locally
+                if (NetworkManager.IsServer)
+                {
+                    networkObject.InvokeBehaviourOnGainedOwnership();
+                }
+            }
+            else if (isRemoving)
+            {
+                OwnershipToObjectsTable[previousOwner].Remove(networkObject.NetworkObjectId);
+            }
+            else if (NetworkManager.LogLevel == LogLevel.Developer)
+            {
+                NetworkLog.LogWarning($"Setting ownership twice? Client-ID {previousOwner} already owns NetworkObject ID {networkObject.NetworkObjectId}!");
+            }
+        }
+
+        /// <summary>
+        /// Returns a list of all NetworkObjects that belong to a client.
+        /// </summary>
+        /// <param name="clientId">the client's id  <see cref="NetworkManager.LocalClientId"/></param>
+        public List<NetworkObject> GetClientOwnedObjects(ulong clientId)
+        {
+            if (!OwnershipToObjectsTable.ContainsKey(clientId))
+            {
+                OwnershipToObjectsTable.Add(clientId, new Dictionary<ulong, NetworkObject>());
+            }
+            return OwnershipToObjectsTable[clientId].Values.ToList();
+        }
+
+
         private struct TriggerData
         {
             public FastBufferReader Reader;
@@ -96,8 +212,7 @@ namespace Unity.Netcode
         /// <summary>
         /// Defers processing of a message until the moment a specific networkObjectId is spawned.
         /// This is to handle situations where an RPC or other object-specific message arrives before the spawn does,
-        /// either due to it being requested in OnNetworkSpawn before the spawn call has been executed, or with
-        /// snapshot spawns enabled where the spawn is sent unreliably and not until the end of the frame.
+        /// either due to it being requested in OnNetworkSpawn before the spawn call has been executed
         ///
         /// 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.
@@ -194,18 +309,10 @@ namespace Unity.Netcode
                 return;
             }
 
-            // Make sure the connected client entry exists before trying to remove ownership.
-            if (TryGetNetworkClient(networkObject.OwnerClientId, out NetworkClient networkClient))
-            {
-                for (int i = networkClient.OwnedObjects.Count - 1; i > -1; i--)
-                {
-                    if (networkClient.OwnedObjects[i] == networkObject)
-                    {
-                        networkClient.OwnedObjects.RemoveAt(i);
-                    }
-                }
+            // Server removes the entry and takes over ownership before notifying
+            UpdateOwnershipTable(networkObject, NetworkManager.ServerClientId, true);
 
-                networkObject.OwnerClientIdInternal = null;
+            networkObject.OwnerClientId = NetworkManager.ServerClientId;
 
             var message = new ChangeOwnershipMessage
             {
@@ -219,14 +326,6 @@ namespace Unity.Netcode
                 NetworkManager.NetworkMetrics.TrackOwnershipChangeSent(client.Key, networkObject, size);
             }
         }
-            else
-            {
-                if (NetworkLog.CurrentLogLevel <= LogLevel.Normal)
-                {
-                    NetworkLog.LogWarning($"No connected clients prior to removing ownership for {networkObject.name}.  Make sure you are not initializing or shutting down when removing ownership.");
-                }
-            }
-        }
 
         /// <summary>
         /// Helper function to get a network client for a clientId from the NetworkManager.
@@ -265,25 +364,10 @@ namespace Unity.Netcode
                 throw new SpawnStateException("Object is not spawned");
             }
 
-            if (TryGetNetworkClient(networkObject.OwnerClientId, out NetworkClient networkClient))
-            {
-                for (int i = networkClient.OwnedObjects.Count - 1; i >= 0; i--)
-                {
-                    if (networkClient.OwnedObjects[i] == networkObject)
-                    {
-                        networkClient.OwnedObjects.RemoveAt(i);
-                    }
-                }
-
-                networkClient.OwnedObjects.Add(networkObject);
-            }
-
             networkObject.OwnerClientId = clientId;
 
-            if (TryGetNetworkClient(clientId, out NetworkClient newNetworkClient))
-            {
-                newNetworkClient.OwnedObjects.Add(networkObject);
-            }
+            // Server adds entries for all client ownership
+            UpdateOwnershipTable(networkObject, networkObject.OwnerClientId);
 
             var message = new ChangeOwnershipMessage
             {
@@ -414,7 +498,7 @@ namespace Unity.Netcode
         }
 
         // Ran on both server and client
-        internal void SpawnNetworkObjectLocally(NetworkObject networkObject, ulong networkId, bool sceneObject, bool playerObject, ulong? ownerClientId, bool destroyWithScene)
+        internal void SpawnNetworkObjectLocally(NetworkObject networkObject, ulong networkId, bool sceneObject, bool playerObject, ulong ownerClientId, bool destroyWithScene)
         {
             if (networkObject == null)
             {
@@ -452,15 +536,12 @@ namespace Unity.Netcode
                 throw new SpawnStateException("Object is already spawned");
             }
 
-            if (sceneObject.Header.HasNetworkVariables)
-            {
             networkObject.SetNetworkVariableData(variableData);
-            }
 
             SpawnNetworkObjectLocallyCommon(networkObject, sceneObject.Header.NetworkObjectId, sceneObject.Header.IsSceneObject, sceneObject.Header.IsPlayerObject, sceneObject.Header.OwnerClientId, destroyWithScene);
         }
 
-        private void SpawnNetworkObjectLocallyCommon(NetworkObject networkObject, ulong networkId, bool sceneObject, bool playerObject, ulong? ownerClientId, bool destroyWithScene)
+        private void SpawnNetworkObjectLocallyCommon(NetworkObject networkObject, ulong networkId, bool sceneObject, bool playerObject, ulong ownerClientId, bool destroyWithScene)
         {
             if (SpawnedObjects.ContainsKey(networkId))
             {
@@ -474,35 +555,42 @@ namespace Unity.Netcode
             // this initialization really should be at the top of this function. If and when we break the
             //  NetworkVariable dependency on NetworkBehaviour, this otherwise creates problems because
             //  SetNetworkVariableData above calls InitializeVariables, and the 'baked out' data isn't ready there;
-            //  the current design banks on getting the network behaviour set and then only reading from it
-            //  after the below initialization code.  However cowardice compels me to hold off on moving this until
-            //  that commit
+            //  the current design banks on getting the network behaviour set and then only reading from it after the
+            //  below initialization code. However cowardice compels me to hold off on moving this until that commit
             networkObject.IsSceneObject = sceneObject;
             networkObject.NetworkObjectId = networkId;
 
             networkObject.DestroyWithScene = sceneObject || destroyWithScene;
 
-            networkObject.OwnerClientIdInternal = ownerClientId;
+            networkObject.OwnerClientId = ownerClientId;
+
             networkObject.IsPlayerObject = playerObject;
 
             SpawnedObjects.Add(networkObject.NetworkObjectId, networkObject);
             SpawnedObjectsList.Add(networkObject);
 
-            if (ownerClientId != null)
-            {
             if (NetworkManager.IsServer)
             {
                 if (playerObject)
                 {
-                        NetworkManager.ConnectedClients[ownerClientId.Value].PlayerObject = networkObject;
-                    }
-                    else
+                    // If there was an already existing player object for this player, then mark it as no longer
+                    // a player object.
+                    if (NetworkManager.ConnectedClients[ownerClientId].PlayerObject != null)
                     {
-                        NetworkManager.ConnectedClients[ownerClientId.Value].OwnedObjects.Add(networkObject);
+                        NetworkManager.ConnectedClients[ownerClientId].PlayerObject.IsPlayerObject = false;
+                    }
+                    NetworkManager.ConnectedClients[ownerClientId].PlayerObject = networkObject;
                 }
             }
-                else if (playerObject && ownerClientId.Value == NetworkManager.LocalClientId)
+            else if (ownerClientId == NetworkManager.LocalClientId)
             {
+                if (playerObject)
+                {
+                    // If there was an already existing player object for this player, then mark it as no longer a player object.
+                    if (NetworkManager.LocalClient.PlayerObject != null)
+                    {
+                        NetworkManager.LocalClient.PlayerObject.IsPlayerObject = false;
+                    }
                     NetworkManager.LocalClient.PlayerObject = networkObject;
                 }
             }
@@ -549,11 +637,8 @@ namespace Unity.Netcode
 
         internal void SendSpawnCallForObject(ulong clientId, NetworkObject networkObject)
         {
-            if (!NetworkManager.NetworkConfig.UseSnapshotSpawn)
-            {
-                //Currently, if this is called and the clientId (destination) is the server's client Id, this case
-                //will be checked within the below Send function.  To avoid unwarranted allocation of a PooledNetworkBuffer
-                //placing this check here. [NSS]
+            //Currently, if this is called and the clientId (destination) is the server's client Id, this case will be checked
+            // within the below Send function.  To avoid unwarranted allocation of a PooledNetworkBuffer placing this check here. [NSS]
             if (NetworkManager.IsServer && clientId == NetworkManager.ServerClientId)
             {
                 return;
@@ -568,7 +653,6 @@ namespace Unity.Netcode
 
             networkObject.MarkVariablesDirty();
         }
-        }
 
         internal ulong? GetSpawnParentId(NetworkObject networkObject)
         {
@@ -605,16 +689,14 @@ namespace Unity.Netcode
         // Makes scene objects ready to be reused
         internal void ServerResetShudownStateForSceneObjects()
         {
-            foreach (var sobj in SpawnedObjectsList)
-            {
-                if ((sobj.IsSceneObject != null && sobj.IsSceneObject == true) || sobj.DestroyWithScene)
+            var networkObjects = UnityEngine.Object.FindObjectsOfType<NetworkObject>().Where((c) => c.IsSceneObject != null && c.IsSceneObject == true);
+            foreach (var sobj in networkObjects)
             {
                 sobj.IsSpawned = false;
                 sobj.DestroyWithScene = false;
                 sobj.IsSceneObject = null;
             }
         }
-        }
 
         /// <summary>
         /// Gets called only by NetworkSceneManager.SwitchScene
@@ -653,14 +735,12 @@ namespace Unity.Netcode
                     else if (networkObjects[i].IsSpawned)
                     {
                         // If it is an in-scene placed NetworkObject then just despawn
-                        // and let it be destroyed when the scene is unloaded.  Otherwise,
-                        // despawn and destroy it.
-                        var shouldDestroy = !(networkObjects[i].IsSceneObject != null
-                                    && networkObjects[i].IsSceneObject.Value);
+                        // and let it be destroyed when the scene is unloaded. Otherwise, despawn and destroy it.
+                        var shouldDestroy = !(networkObjects[i].IsSceneObject != null && networkObjects[i].IsSceneObject.Value);
 
                         OnDespawnObject(networkObjects[i], shouldDestroy);
                     }
-                    else
+                    else if (networkObjects[i].IsSceneObject != null && !networkObjects[i].IsSceneObject.Value)
                     {
                         UnityEngine.Object.Destroy(networkObjects[i].gameObject);
                     }
@@ -711,9 +791,10 @@ namespace Unity.Netcode
                 }
             }
 
+
             foreach (var networkObject in networkObjectsToSpawn)
             {
-                SpawnNetworkObjectLocally(networkObject, GetNetworkObjectId(), true, false, null, true);
+                SpawnNetworkObjectLocally(networkObject, GetNetworkObjectId(), true, false, networkObject.OwnerClientId, true);
             }
         }
 
@@ -757,18 +838,6 @@ namespace Unity.Netcode
                 }
             }
 
-            if (!networkObject.IsOwnedByServer && !networkObject.IsPlayerObject && TryGetNetworkClient(networkObject.OwnerClientId, out NetworkClient networkClient))
-            {
-                //Someone owns it.
-                for (int i = networkClient.OwnedObjects.Count - 1; i > -1; i--)
-                {
-                    if (networkClient.OwnedObjects[i].NetworkObjectId == networkObject.NetworkObjectId)
-                    {
-                        networkClient.OwnedObjects.RemoveAt(i);
-                    }
-                }
-            }
-
             networkObject.InvokeBehaviourNetworkDespawn();
 
             if (NetworkManager != null && NetworkManager.IsServer)
@@ -782,12 +851,6 @@ namespace Unity.Netcode
                     });
                 }
 
-                if (NetworkManager.NetworkConfig.UseSnapshotSpawn)
-                {
-                    networkObject.SnapshotDespawn();
-                }
-                else
-                {
                 if (networkObject != null)
                 {
                     // As long as we have any remaining clients, then notify of the object being destroy.
@@ -817,7 +880,6 @@ namespace Unity.Netcode
                     }
                 }
             }
-            }
 
             networkObject.IsSpawned = false;
 

Runtime/Transports/UNET/UNetChannel.cs

@@ -1,54 +0,0 @@
-#if UNITY_UNET_PRESENT
-using System;
-#if UNITY_EDITOR
-using UnityEditor;
-#endif
-using UnityEngine;
-using UnityEngine.Networking;
-
-namespace Unity.Netcode.Transports.UNET
-{
-    /// <summary>
-    /// A transport channel used by the netcode
-    /// </summary>
-    [Serializable]
-    public class UNetChannel
-    {
-        /// <summary>
-        /// The name of the channel
-        /// </summary>
-#if UNITY_EDITOR
-        [ReadOnly]
-#endif
-        public byte Id;
-
-        /// <summary>
-        /// The type of channel
-        /// </summary>
-        public QosType Type;
-
-#if UNITY_EDITOR
-        private class ReadOnlyAttribute : PropertyAttribute { }
-
-        [CustomPropertyDrawer(typeof(ReadOnlyAttribute))]
-        private class ReadOnlyDrawer : PropertyDrawer
-        {
-            public override void OnGUI(Rect position, SerializedProperty property, GUIContent label)
-            {
-                // Saving previous GUI enabled value
-                var previousGUIState = GUI.enabled;
-
-                // Disabling edit for property
-                GUI.enabled = false;
-
-                // Drawing Property
-                EditorGUI.PropertyField(position, property, label);
-
-                // Setting old GUI enabled value
-                GUI.enabled = previousGUIState;
-            }
-        }
-#endif
-    }
-}
-#endif

Runtime/Transports/UNET/UNetChannel.cs.meta

@@ -1,11 +0,0 @@
-fileFormatVersion: 2
-guid: e864534da30ef604992c0ed33c75d3c6
-MonoImporter:
-  externalObjects: {}
-  serializedVersion: 2
-  defaultReferences: []
-  executionOrder: 0
-  icon: {instanceID: 0}
-  userData: 
-  assetBundleName: 
-  assetBundleVariant: 

Runtime/Transports/UTP.meta

@@ -0,0 +1,8 @@
+fileFormatVersion: 2
+guid: 81887adf6d9ca40c9b70728b7018b6f5
+folderAsset: yes
+DefaultImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Runtime/Transports/UTP/BatchedReceiveQueue.cs

@@ -0,0 +1,96 @@
+using System;
+using Unity.Networking.Transport;
+
+namespace Unity.Netcode.Transports.UTP
+{
+    /// <summary>Queue for batched messages received through UTP.</summary>
+    /// <remarks>This is meant as a companion to <see cref="BatchedSendQueue"/>.</remarks>
+    internal class BatchedReceiveQueue
+    {
+        private byte[] m_Data;
+        private int m_Offset;
+        private int m_Length;
+
+        public bool IsEmpty => m_Length <= 0;
+
+        /// <summary>
+        /// Construct a new receive queue from a <see cref="DataStreamReader"/> returned by
+        /// <see cref="NetworkDriver"/> when popping a data event.
+        /// </summary>
+        /// <param name="reader">The <see cref="DataStreamReader"/> to construct from.</param>
+        public BatchedReceiveQueue(DataStreamReader reader)
+        {
+            m_Data = new byte[reader.Length];
+            unsafe
+            {
+                fixed (byte* dataPtr = m_Data)
+                {
+                    reader.ReadBytes(dataPtr, reader.Length);
+                }
+            }
+
+            m_Offset = 0;
+            m_Length = reader.Length;
+        }
+
+        /// <summary>
+        /// Push the entire data from a <see cref="DataStreamReader"/> (as returned by popping an
+        /// event from a <see cref="NetworkDriver">) to the queue.
+        /// </summary>
+        /// <param name="reader">The <see cref="DataStreamReader"/> to push the data of.</param>
+        public void PushReader(DataStreamReader reader)
+        {
+            // Resize the array and copy the existing data to the beginning if there's not enough
+            // room to copy the reader's data at the end of the existing data.
+            var available = m_Data.Length - (m_Offset + m_Length);
+            if (available < reader.Length)
+            {
+                if (m_Length > 0)
+                {
+                    Array.Copy(m_Data, m_Offset, m_Data, 0, m_Length);
+                }
+
+                m_Offset = 0;
+
+                while (m_Data.Length - m_Length < reader.Length)
+                {
+                    Array.Resize(ref m_Data, m_Data.Length * 2);
+                }
+            }
+
+            unsafe
+            {
+                fixed (byte* dataPtr = m_Data)
+                {
+                    reader.ReadBytes(dataPtr + m_Offset + m_Length, reader.Length);
+                }
+            }
+
+            m_Length += reader.Length;
+        }
+
+        /// <summary>Pop the next full message in the queue.</summary>
+        /// <returns>The message, or the default value if no more full messages.</returns>
+        public ArraySegment<byte> PopMessage()
+        {
+            if (m_Length < sizeof(int))
+            {
+                return default;
+            }
+
+            var messageLength = BitConverter.ToInt32(m_Data, m_Offset);
+
+            if (m_Length - sizeof(int) < messageLength)
+            {
+                return default;
+            }
+
+            var data = new ArraySegment<byte>(m_Data, m_Offset + sizeof(int), messageLength);
+
+            m_Offset += sizeof(int) + messageLength;
+            m_Length -= sizeof(int) + messageLength;
+
+            return data;
+        }
+    }
+}

Runtime/Transports/UTP/BatchedReceiveQueue.cs.meta

@@ -1,5 +1,5 @@
 fileFormatVersion: 2
-guid: a32aeecf69a2542469927066f5b88005
+guid: e9ead10b891184bd5b8f2650fd66a5b1
 MonoImporter:
   externalObjects: {}
   serializedVersion: 2

Runtime/Transports/UTP/BatchedSendQueue.cs

@@ -0,0 +1,233 @@
+using System;
+using Unity.Collections;
+using Unity.Collections.LowLevel.Unsafe;
+using Unity.Networking.Transport;
+
+namespace Unity.Netcode.Transports.UTP
+{
+    /// <summary>Queue for batched messages meant to be sent through UTP.</summary>
+    /// <remarks>
+    /// Messages should be pushed on the queue with <see cref="PushMessage"/>. To send batched
+    /// messages, call <see cref="FillWriter"> with the <see cref="DataStreamWriter"/> obtained from
+    /// <see cref="NetworkDriver.BeginSend"/>. This will fill the writer with as many messages as
+    /// possible. If the send is successful, call <see cref="Consume"/> to remove the data from the
+    /// queue.
+    ///
+    /// This is meant as a companion to <see cref="BatchedReceiveQueue"/>, which should be used to
+    /// read messages sent with this queue.
+    /// </remarks>
+    internal struct BatchedSendQueue : IDisposable
+    {
+        private NativeArray<byte> m_Data;
+        private NativeArray<int> m_HeadTailIndices;
+
+        /// <summary>Overhead that is added to each message in the queue.</summary>
+        public const int PerMessageOverhead = sizeof(int);
+
+        // Indices into m_HeadTailIndicies.
+        private const int k_HeadInternalIndex = 0;
+        private const int k_TailInternalIndex = 1;
+
+        /// <summary>Index of the first byte of the oldest data in the queue.</summary>
+        private int HeadIndex
+        {
+            get { return m_HeadTailIndices[k_HeadInternalIndex]; }
+            set { m_HeadTailIndices[k_HeadInternalIndex] = value; }
+        }
+
+        /// <summary>Index one past the last byte of the most recent data in the queue.</summary>
+        private int TailIndex
+        {
+            get { return m_HeadTailIndices[k_TailInternalIndex]; }
+            set { m_HeadTailIndices[k_TailInternalIndex] = value; }
+        }
+
+        public int Length => TailIndex - HeadIndex;
+
+        public bool IsEmpty => HeadIndex == TailIndex;
+
+        public bool IsCreated => m_Data.IsCreated;
+
+        /// <summary>Construct a new empty send queue.</summary>
+        /// <param name="capacity">Maximum capacity of the send queue.</param>
+        public BatchedSendQueue(int capacity)
+        {
+            m_Data = new NativeArray<byte>(capacity, Allocator.Persistent);
+            m_HeadTailIndices = new NativeArray<int>(2, Allocator.Persistent);
+
+            HeadIndex = 0;
+            TailIndex = 0;
+        }
+
+        public void Dispose()
+        {
+            if (IsCreated)
+            {
+                m_Data.Dispose();
+                m_HeadTailIndices.Dispose();
+            }
+        }
+
+        /// <summary>Append data at the tail of the queue. No safety checks.</summary>
+        private void AppendDataAtTail(ArraySegment<byte> data)
+        {
+            unsafe
+            {
+                var writer = new DataStreamWriter((byte*)m_Data.GetUnsafePtr() + TailIndex, m_Data.Length - TailIndex);
+
+                writer.WriteInt(data.Count);
+
+                fixed (byte* dataPtr = data.Array)
+                {
+                    writer.WriteBytes(dataPtr + data.Offset, data.Count);
+                }
+            }
+
+            TailIndex += sizeof(int) + data.Count;
+        }
+
+        /// <summary>Append a new message to the queue.</summary>
+        /// <param name="message">Message to append to the queue.</param>
+        /// <returns>
+        /// Whether the message was appended successfully. The only way it can fail is if there's
+        /// no more room in the queue. On failure, nothing is written to the queue.
+        /// </returns>
+        public bool PushMessage(ArraySegment<byte> message)
+        {
+            if (!IsCreated)
+            {
+                return false;
+            }
+
+            // Check if there's enough room after the current tail index.
+            if (m_Data.Length - TailIndex >= sizeof(int) + message.Count)
+            {
+                AppendDataAtTail(message);
+                return true;
+            }
+
+            // Check if there would be enough room if we moved data at the beginning of m_Data.
+            if (m_Data.Length - TailIndex + HeadIndex >= sizeof(int) + message.Count)
+            {
+                // Move the data back at the beginning of m_Data.
+                unsafe
+                {
+                    UnsafeUtility.MemMove(m_Data.GetUnsafePtr(), (byte*)m_Data.GetUnsafePtr() + HeadIndex, Length);
+                }
+
+                TailIndex = Length;
+                HeadIndex = 0;
+
+                AppendDataAtTail(message);
+                return true;
+            }
+
+            return false;
+        }
+
+        /// <summary>
+        /// Fill as much of a <see cref="DataStreamWriter"/> as possible with data from the head of
+        /// the queue. Only full messages (and their length) are written to the writer.
+        /// </summary>
+        /// <remarks>
+        /// This does NOT actually consume anything from the queue. That is, calling this method
+        /// does not reduce the length of the queue. Callers are expected to call
+        /// <see cref="Consume"/> with the value returned by this method afterwards if the data can
+        /// be safely removed from the queue (e.g. if it was sent successfully).
+        ///
+        /// This method should not be used together with <see cref="FillWriterWithBytes"> since this
+        /// could lead to a corrupted queue.
+        /// </remarks>
+        /// <param name="writer">The <see cref="DataStreamWriter"/> to write to.</param>
+        /// <returns>How many bytes were written to the writer.</returns>
+        public int FillWriterWithMessages(ref DataStreamWriter writer)
+        {
+            if (!IsCreated || Length == 0)
+            {
+                return 0;
+            }
+
+            unsafe
+            {
+                var reader = new DataStreamReader((byte*)m_Data.GetUnsafePtr() + HeadIndex, Length);
+
+                var writerAvailable = writer.Capacity;
+                var readerOffset = 0;
+
+                while (readerOffset < Length)
+                {
+                    reader.SeekSet(readerOffset);
+                    var messageLength = reader.ReadInt();
+
+                    if (writerAvailable < sizeof(int) + messageLength)
+                    {
+                        break;
+                    }
+                    else
+                    {
+                        writer.WriteInt(messageLength);
+
+                        var messageOffset = HeadIndex + reader.GetBytesRead();
+                        writer.WriteBytes((byte*)m_Data.GetUnsafePtr() + messageOffset, messageLength);
+
+                        writerAvailable -= sizeof(int) + messageLength;
+                        readerOffset += sizeof(int) + messageLength;
+                    }
+                }
+
+                return writer.Capacity - writerAvailable;
+            }
+        }
+
+        /// <summary>
+        /// Fill the given <see cref="DataStreamWriter"/> with as many bytes from the queue as
+        /// possible, disregarding message boundaries.
+        /// </summary>
+        ///<remarks>
+        /// This does NOT actually consume anything from the queue. That is, calling this method
+        /// does not reduce the length of the queue. Callers are expected to call
+        /// <see cref="Consume"/> with the value returned by this method afterwards if the data can
+        /// be safely removed from the queue (e.g. if it was sent successfully).
+        ///
+        /// This method should not be used together with <see cref="FillWriterWithMessages"/> since
+        /// this could lead to reading messages from a corrupted queue.
+        /// </remarks>
+        /// <param name="writer">The <see cref="DataStreamWriter"/> to write to.</param>
+        /// <returns>How many bytes were written to the writer.</returns>
+        public int FillWriterWithBytes(ref DataStreamWriter writer)
+        {
+            if (!IsCreated || Length == 0)
+            {
+                return 0;
+            }
+
+            var copyLength = Math.Min(writer.Capacity, Length);
+
+            unsafe
+            {
+                writer.WriteBytes((byte*)m_Data.GetUnsafePtr() + HeadIndex, copyLength);
+            }
+
+            return copyLength;
+        }
+
+        /// <summary>Consume a number of bytes from the head of the queue.</summary>
+        /// <remarks>
+        /// This should only be called with a size that matches the last value returned by
+        /// <see cref="FillWriter"/>. Anything else will result in a corrupted queue.
+        /// </remarks>
+        /// <param name="size">Number of bytes to consume from the queue.</param>
+        public void Consume(int size)
+        {
+            if (size >= Length)
+            {
+                HeadIndex = 0;
+                TailIndex = 0;
+            }
+            else
+            {
+                HeadIndex += size;
+            }
+        }
+    }
+}

Runtime/Transports/UTP/BatchedSendQueue.cs.meta

@@ -1,5 +1,5 @@
 fileFormatVersion: 2
-guid: c275febadb27c4d18b41218e3353b84b
+guid: ddf8f97f695d740f297dc42242b76b8c
 MonoImporter:
   externalObjects: {}
   serializedVersion: 2

Runtime/Transports/UTP/NetworkMetricsContext.cs

@@ -0,0 +1,8 @@
+namespace Unity.Netcode.Transports.UTP
+{
+    public struct NetworkMetricsContext
+    {
+        public uint PacketSentCount;
+        public uint PacketReceivedCount;
+    }
+}

Runtime/Transports/UTP/NetworkMetricsContext.cs.meta

@@ -1,5 +1,5 @@
 fileFormatVersion: 2
-guid: bd9e1475e8c8e4a6d935fe2409e3bd26
+guid: adb0270501ff1421896ce15cc75bd56a
 MonoImporter:
   externalObjects: {}
   serializedVersion: 2

Runtime/Transports/UTP/NetworkMetricsPipelineStage.cs

@@ -0,0 +1,70 @@
+#if MULTIPLAYER_TOOLS
+#if MULTIPLAYER_TOOLS_1_0_0_PRE_7
+using AOT;
+using Unity.Burst;
+using Unity.Collections.LowLevel.Unsafe;
+using Unity.Networking.Transport;
+using UnityEngine;
+
+namespace Unity.Netcode.Transports.UTP
+{
+    [BurstCompile]
+    internal unsafe struct NetworkMetricsPipelineStage : INetworkPipelineStage
+    {
+        static TransportFunctionPointer<NetworkPipelineStage.ReceiveDelegate> ReceiveFunction = new TransportFunctionPointer<NetworkPipelineStage.ReceiveDelegate>(Receive);
+        static TransportFunctionPointer<NetworkPipelineStage.SendDelegate> SendFunction = new TransportFunctionPointer<NetworkPipelineStage.SendDelegate>(Send);
+        static TransportFunctionPointer<NetworkPipelineStage.InitializeConnectionDelegate> InitializeConnectionFunction = new TransportFunctionPointer<NetworkPipelineStage.InitializeConnectionDelegate>(InitializeConnection);
+
+        public NetworkPipelineStage StaticInitialize(byte* staticInstanceBuffer,
+            int staticInstanceBufferLength,
+            NetworkSettings settings)
+        {
+            return new NetworkPipelineStage(
+                ReceiveFunction,
+                SendFunction,
+                InitializeConnectionFunction,
+                ReceiveCapacity: 0,
+                SendCapacity: 0,
+                HeaderCapacity: 0,
+                SharedStateCapacity: UnsafeUtility.SizeOf<NetworkMetricsContext>());
+        }
+
+        public int StaticSize => 0;
+
+        [BurstCompile(DisableDirectCall = true)]
+        [MonoPInvokeCallback(typeof(NetworkPipelineStage.ReceiveDelegate))]
+        private static void Receive(ref NetworkPipelineContext networkPipelineContext,
+            ref InboundRecvBuffer inboundReceiveBuffer,
+            ref NetworkPipelineStage.Requests requests,
+            int systemHeaderSize)
+        {
+            var networkMetricContext = (NetworkMetricsContext*)networkPipelineContext.internalSharedProcessBuffer;
+            networkMetricContext->PacketReceivedCount++;
+        }
+
+        [BurstCompile(DisableDirectCall = true)]
+        [MonoPInvokeCallback(typeof(NetworkPipelineStage.SendDelegate))]
+        private static int Send(ref NetworkPipelineContext networkPipelineContext,
+            ref InboundSendBuffer inboundSendBuffer,
+            ref NetworkPipelineStage.Requests requests,
+            int systemHeaderSize)
+        {
+            var networkMetricContext = (NetworkMetricsContext*)networkPipelineContext.internalSharedProcessBuffer;
+            networkMetricContext->PacketSentCount++;
+            return 0;
+        }
+
+        [BurstCompile(DisableDirectCall = true)]
+        [MonoPInvokeCallback(typeof(NetworkPipelineStage.InitializeConnectionDelegate))]
+        private static void InitializeConnection(byte* staticInstanceBuffer, int staticInstanceBufferLength,
+            byte* sendProcessBuffer, int sendProcessBufferLength, byte* receiveProcessBuffer, int receiveProcessBufferLength,
+            byte* sharedProcessBuffer, int sharedProcessBufferLength)
+        {
+            var networkMetricContext = (NetworkMetricsContext*)sharedProcessBuffer;
+            networkMetricContext->PacketSentCount = 0;
+            networkMetricContext->PacketReceivedCount = 0;
+        }
+    }
+}
+#endif
+#endif

Runtime/Transports/UTP/NetworkMetricsPipelineStage.cs.meta

@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 52b1ce9f83ce049c59327064bf70cee8
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Runtime/Transports/UTP/UnityTransport.cs.meta

@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 6960e84d07fb87f47956e7a81d71c4e6
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Runtime/com.unity.netcode.runtime.asmdef

@@ -10,7 +10,9 @@
         "Unity.Multiplayer.Tools.NetStats",
         "Unity.Multiplayer.Tools.NetStatsReporting",
         "Unity.Multiplayer.Tools.NetworkSolutionInterface",
-        "Unity.Collections"
+        "Unity.Networking.Transport",
+        "Unity.Collections",
+        "Unity.Burst"
     ],
     "allowUnsafeCode": true,
     "versionDefines": [
@@ -26,8 +28,8 @@
         },
         {
             "name": "com.unity.multiplayer.tools",
-            "expression": "1.0.0-pre.4",
-            "define": "MULTIPLAYER_TOOLS_1_0_0_PRE_4"
+            "expression": "1.0.0-pre.7",
+            "define": "MULTIPLAYER_TOOLS_1_0_0_PRE_7"
         }
     ]
 }

TestHelpers/Runtime/NetcodeIntegrationTest.cs

@@ -5,6 +5,7 @@ using System.Linq;
 using NUnit.Framework;
 using UnityEngine;
 using UnityEngine.TestTools;
+using System.Runtime.CompilerServices;
 
 using Object = UnityEngine.Object;
 
@@ -111,6 +112,33 @@ namespace Unity.Netcode.TestHelpers.Runtime
 
         private NetworkManagerInstatiationMode m_NetworkManagerInstatiationMode;
 
+        private bool m_EnableVerboseDebug;
+
+        /// <summary>
+        /// Used to display the various integration test
+        /// stages and can be used to log verbose information
+        /// for troubleshooting an integration test.
+        /// </summary>
+        /// <param name="msg"></param>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        protected void VerboseDebug(string msg)
+        {
+            if (m_EnableVerboseDebug)
+            {
+                Debug.Log(msg);
+            }
+        }
+
+        /// <summary>
+        /// Override this and return true if you need
+        /// to troubleshoot a hard to track bug within an
+        /// integration test.
+        /// </summary>
+        protected virtual bool OnSetVerboseDebug()
+        {
+            return false;
+        }
+
         /// <summary>
         /// The very first thing invoked during the <see cref="OneTimeSetup"/> that
         /// determines how this integration test handles NetworkManager instantiation
@@ -130,11 +158,17 @@ namespace Unity.Netcode.TestHelpers.Runtime
         [OneTimeSetUp]
         public void OneTimeSetup()
         {
+            m_EnableVerboseDebug = OnSetVerboseDebug();
+
+            VerboseDebug($"Entering {nameof(OneTimeSetup)}");
+
             m_NetworkManagerInstatiationMode = OnSetIntegrationTestMode();
 
             // Enable NetcodeIntegrationTest auto-label feature
             NetcodeIntegrationTestHelpers.RegisterNetcodeIntegrationTest(true);
             OnOneTimeSetup();
+
+            VerboseDebug($"Exiting {nameof(OneTimeSetup)}");
         }
 
         /// <summary>
@@ -153,6 +187,8 @@ namespace Unity.Netcode.TestHelpers.Runtime
         [UnitySetUp]
         public IEnumerator SetUp()
         {
+            VerboseDebug($"Entering {nameof(SetUp)}");
+
             yield return OnSetup();
             if (m_NetworkManagerInstatiationMode == NetworkManagerInstatiationMode.AllTests && m_ServerNetworkManager == null ||
                 m_NetworkManagerInstatiationMode == NetworkManagerInstatiationMode.PerTest)
@@ -161,6 +197,7 @@ namespace Unity.Netcode.TestHelpers.Runtime
 
                 yield return StartServerAndClients();
             }
+            VerboseDebug($"Exiting {nameof(SetUp)}");
         }
 
         /// <summary>
@@ -173,6 +210,7 @@ namespace Unity.Netcode.TestHelpers.Runtime
 
         private void CreatePlayerPrefab()
         {
+            VerboseDebug($"Entering {nameof(CreatePlayerPrefab)}");
             // Create playerPrefab
             m_PlayerPrefab = new GameObject("Player");
             NetworkObject networkObject = m_PlayerPrefab.AddComponent<NetworkObject>();
@@ -181,6 +219,8 @@ namespace Unity.Netcode.TestHelpers.Runtime
             NetcodeIntegrationTestHelpers.MakeNetworkObjectTestPrefab(networkObject);
 
             OnCreatePlayerPrefab();
+
+            VerboseDebug($"Exiting {nameof(CreatePlayerPrefab)}");
         }
 
         /// <summary>
@@ -207,6 +247,8 @@ namespace Unity.Netcode.TestHelpers.Runtime
         /// <param name="numberOfClients"></param>
         protected void CreateServerAndClients(int numberOfClients)
         {
+            VerboseDebug($"Entering {nameof(CreateServerAndClients)}");
+
             CreatePlayerPrefab();
 
             // Create multiple NetworkManager instances
@@ -235,6 +277,8 @@ namespace Unity.Netcode.TestHelpers.Runtime
             // Provides opportunity to allow child derived classes to
             // modify the NetworkManager's configuration before starting.
             OnServerAndClientsCreated();
+
+            VerboseDebug($"Exiting {nameof(CreateServerAndClients)}");
         }
 
         /// <summary>
@@ -272,6 +316,8 @@ namespace Unity.Netcode.TestHelpers.Runtime
         {
             if (CanStartServerAndClients())
             {
+                VerboseDebug($"Entering {nameof(StartServerAndClients)}");
+
                 // Start the instances and pass in our SceneManagerInitialization action that is invoked immediately after host-server
                 // is started and after each client is started.
                 if (!NetcodeIntegrationTestHelpers.Start(m_UseHost, m_ServerNetworkManager, m_ClientNetworkManagers))
@@ -290,11 +336,6 @@ namespace Unity.Netcode.TestHelpers.Runtime
 
                 Assert.False(s_GlobalTimeoutHelper.TimedOut, $"{nameof(StartServerAndClients)} timed out waiting for all clients to be connected!");
 
-                if (s_GlobalTimeoutHelper.TimedOut)
-                {
-                    yield return null;
-                }
-
                 if (m_UseHost || m_ServerNetworkManager.IsHost)
                 {
                     // Add the server player instance to all m_ClientSidePlayerNetworkObjects entries
@@ -332,6 +373,8 @@ namespace Unity.Netcode.TestHelpers.Runtime
                 // Notification that at this time the server and client(s) are instantiated,
                 // started, and connected on both sides.
                 yield return OnServerAndClientsConnected();
+
+                VerboseDebug($"Exiting {nameof(StartServerAndClients)}");
             }
         }
 
@@ -398,6 +441,7 @@ namespace Unity.Netcode.TestHelpers.Runtime
         /// </summary>
         protected void ShutdownAndCleanUp()
         {
+            VerboseDebug($"Entering {nameof(ShutdownAndCleanUp)}");
             // Shutdown and clean up both of our NetworkManager instances
             try
             {
@@ -427,6 +471,7 @@ namespace Unity.Netcode.TestHelpers.Runtime
 
             // reset the m_ServerWaitForTick for the next test to initialize
             s_DefaultWaitForTick = new WaitForSeconds(1.0f / k_DefaultTickRate);
+            VerboseDebug($"Exiting {nameof(ShutdownAndCleanUp)}");
         }
 
         /// <summary>
@@ -441,12 +486,15 @@ namespace Unity.Netcode.TestHelpers.Runtime
         [UnityTearDown]
         public IEnumerator TearDown()
         {
+            VerboseDebug($"Entering {nameof(TearDown)}");
             yield return OnTearDown();
 
             if (m_NetworkManagerInstatiationMode == NetworkManagerInstatiationMode.PerTest)
             {
                 ShutdownAndCleanUp();
             }
+
+            VerboseDebug($"Exiting {nameof(TearDown)}");
         }
 
         /// <summary>
@@ -462,6 +510,7 @@ namespace Unity.Netcode.TestHelpers.Runtime
         [OneTimeTearDown]
         public void OneTimeTearDown()
         {
+            VerboseDebug($"Entering {nameof(OneTimeTearDown)}");
             OnOneTimeTearDown();
 
             if (m_NetworkManagerInstatiationMode == NetworkManagerInstatiationMode.AllTests)
@@ -471,6 +520,8 @@ namespace Unity.Netcode.TestHelpers.Runtime
 
             // Disable NetcodeIntegrationTest auto-label feature
             NetcodeIntegrationTestHelpers.RegisterNetcodeIntegrationTest(false);
+
+            VerboseDebug($"Exiting {nameof(OneTimeTearDown)}");
         }
 
         /// <summary>

TestHelpers/Runtime/NetcodeIntegrationTestHelpers.cs

@@ -3,6 +3,7 @@ using System.Collections;
 using System.Collections.Generic;
 using System.Linq;
 using NUnit.Framework;
+using Unity.Netcode.Transports.UTP;
 using UnityEngine;
 using UnityEngine.SceneManagement;
 using Object = UnityEngine.Object;
@@ -109,9 +110,7 @@ namespace Unity.Netcode.TestHelpers.Runtime
         public enum InstanceTransport
         {
             SIP,
-#if UTP_ADAPTER
             UTP
-#endif
         }
 
         internal static IntegrationTestSceneHandler ClientSceneHandler = null;
@@ -172,12 +171,10 @@ namespace Unity.Netcode.TestHelpers.Runtime
             switch (instanceTransport)
             {
                 case InstanceTransport.SIP:
-                default:
                     return go.AddComponent<SIPTransport>();
-#if UTP_ADAPTER
+                default:
                 case InstanceTransport.UTP:
                     return go.AddComponent<UnityTransport>();
-#endif
             }
         }
 

TestHelpers/Runtime/com.unity.netcode.testhelpers.runtime.asmdef

@@ -3,7 +3,6 @@
     "rootNamespace": "Unity.Netcode.TestHelpers.Runtime",
     "references": [
         "Unity.Netcode.Runtime",
-        "Unity.Netcode.Adapter.UTP",
         "Unity.Multiplayer.MetricTypes",
         "Unity.Multiplayer.NetStats",
         "Unity.Multiplayer.Tools.MetricTypes",
@@ -18,15 +17,10 @@
             "expression": "",
             "define": "MULTIPLAYER_TOOLS"
         },
-        {
-            "name": "com.unity.netcode.adapter.utp",
-            "expression": "",
-            "define": "UTP_ADAPTER"
-        },
         {
             "name": "com.unity.multiplayer.tools",
-            "expression": "1.0.0-pre.4",
-            "define": "MULTIPLAYER_TOOLS_1_0_0_PRE_4"
+            "expression": "1.0.0-pre.7",
+            "define": "MULTIPLAYER_TOOLS_1_0_0_PRE_7"
         }
     ]
 }

Tests/Editor/IndexAllocatorTests.cs

@@ -1,116 +0,0 @@
-using NUnit.Framework;
-using UnityEngine;
-
-namespace Unity.Netcode.EditorTests
-{
-    public class FixedAllocatorTest
-    {
-        [Test]
-        public void SimpleTest()
-        {
-            int pos;
-
-            var allocator = new IndexAllocator(20000, 200);
-            allocator.DebugDisplay();
-
-            // allocate 20 bytes
-            Assert.IsTrue(allocator.Allocate(0, 20, out pos));
-            allocator.DebugDisplay();
-            Assert.IsTrue(allocator.Verify());
-
-            // can't ask for negative amount of memory
-            Assert.IsFalse(allocator.Allocate(1, -20, out pos));
-            Assert.IsTrue(allocator.Verify());
-
-            // can't ask for deallocation of negative index
-            Assert.IsFalse(allocator.Deallocate(-1));
-            Assert.IsTrue(allocator.Verify());
-
-            // can't ask for the same index twice
-            Assert.IsFalse(allocator.Allocate(0, 20, out pos));
-            Assert.IsTrue(allocator.Verify());
-
-            // allocate another 20 bytes
-            Assert.IsTrue(allocator.Allocate(1, 20, out pos));
-            allocator.DebugDisplay();
-            Assert.IsTrue(allocator.Verify());
-
-            // allocate a third 20 bytes
-            Assert.IsTrue(allocator.Allocate(2, 20, out pos));
-            allocator.DebugDisplay();
-            Assert.IsTrue(allocator.Verify());
-
-            // deallocate 0
-            Assert.IsTrue(allocator.Deallocate(0));
-            allocator.DebugDisplay();
-            Assert.IsTrue(allocator.Verify());
-
-            // deallocate 1
-            allocator.Deallocate(1);
-            allocator.DebugDisplay();
-            Assert.IsTrue(allocator.Verify());
-
-            // deallocate 2
-            allocator.Deallocate(2);
-            allocator.DebugDisplay();
-            Assert.IsTrue(allocator.Verify());
-
-            // allocate 50 bytes
-            Assert.IsTrue(allocator.Allocate(0, 50, out pos));
-            allocator.DebugDisplay();
-            Assert.IsTrue(allocator.Verify());
-
-            // allocate another 50 bytes
-            Assert.IsTrue(allocator.Allocate(1, 50, out pos));
-            allocator.DebugDisplay();
-            Assert.IsTrue(allocator.Verify());
-
-            // allocate a third 50 bytes
-            Assert.IsTrue(allocator.Allocate(2, 50, out pos));
-            allocator.DebugDisplay();
-            Assert.IsTrue(allocator.Verify());
-
-            // deallocate 1, a block in the middle this time
-            allocator.Deallocate(1);
-            allocator.DebugDisplay();
-            Assert.IsTrue(allocator.Verify());
-
-            // allocate a smaller one in its place
-            allocator.Allocate(1, 25, out pos);
-            allocator.DebugDisplay();
-            Assert.IsTrue(allocator.Verify());
-        }
-
-        [Test]
-        public void ReuseTest()
-        {
-            int count = 100;
-            bool[] used = new bool[count];
-            int[] pos = new int[count];
-            int iterations = 10000;
-
-            var allocator = new IndexAllocator(20000, 200);
-
-            for (int i = 0; i < iterations; i++)
-            {
-                int index = Random.Range(0, count);
-                if (used[index])
-                {
-                    Assert.IsTrue(allocator.Deallocate(index));
-                    used[index] = false;
-                }
-                else
-                {
-                    int position;
-                    int length = 10 * Random.Range(1, 10);
-                    Assert.IsTrue(allocator.Allocate(index, length, out position));
-                    pos[index] = position;
-                    used[index] = true;
-                }
-                Assert.IsTrue(allocator.Verify());
-            }
-            allocator.DebugDisplay();
-        }
-
-    }
-}

Tests/Editor/IndexAllocatorTests.cs.meta

@@ -1,11 +0,0 @@
-fileFormatVersion: 2
-guid: 85ac488e1432d49668c711fa625a0743
-MonoImporter:
-  externalObjects: {}
-  serializedVersion: 2
-  defaultReferences: []
-  executionOrder: 0
-  icon: {instanceID: 0}
-  userData: 
-  assetBundleName: 
-  assetBundleVariant: 

Tests/Editor/NetworkManagerConfigurationTests.cs

@@ -34,5 +34,49 @@ namespace Unity.Netcode.EditorTests
             // Clean up
             Object.DestroyImmediate(parent);
         }
+
+        public enum NetworkObjectPlacement
+        {
+            Root,   // Added to the same root GameObject
+            Child   // Added to a child GameObject
+        }
+
+        [Test]
+        public void NetworkObjectNotAllowed([Values] NetworkObjectPlacement networkObjectPlacement)
+        {
+            var gameObject = new GameObject(nameof(NetworkManager));
+            var targetforNetworkObject = gameObject;
+
+            if (networkObjectPlacement == NetworkObjectPlacement.Child)
+            {
+                var childGameObject = new GameObject($"{nameof(NetworkManager)}-Child");
+                childGameObject.transform.parent = targetforNetworkObject.transform;
+                targetforNetworkObject = childGameObject;
+            }
+
+            var networkManager = gameObject.AddComponent<NetworkManager>();
+
+            // Trap for the error message generated when a NetworkObject is discovered on the same GameObject or any children under it
+            LogAssert.Expect(LogType.Error, NetworkManagerHelper.Singleton.NetworkManagerAndNetworkObjectNotAllowedMessage());
+
+            // Add the NetworkObject
+            var networkObject = targetforNetworkObject.AddComponent<NetworkObject>();
+
+            // Since this is an in-editor test, we must force this invocation
+            NetworkManagerHelper.Singleton.CheckAndNotifyUserNetworkObjectRemoved(networkManager, true);
+
+            // Validate that the NetworkObject has been removed
+            if (networkObjectPlacement == NetworkObjectPlacement.Root)
+            {
+                Assert.IsNull(networkManager.gameObject.GetComponent<NetworkObject>(), $"There is still a {nameof(NetworkObject)} on {nameof(NetworkManager)}'s GameObject!");
+            }
+            else
+            {
+                Assert.IsNull(networkManager.gameObject.GetComponentInChildren<NetworkObject>(), $"There is still a {nameof(NetworkObject)} on {nameof(NetworkManager)}'s child GameObject!");
+            }
+
+            // Clean up
+            Object.DestroyImmediate(gameObject);
+        }
     }
 }

Tests/Editor/NetworkVar.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: ed3be13d96c34bc4b8676ce550cee041
+timeCreated: 1647861659

Tests/Editor/NetworkVar/NetworkVarTests.cs

@@ -0,0 +1,41 @@
+using NUnit.Framework;
+
+namespace Unity.Netcode.EditorTests.NetworkVar
+{
+    public class NetworkVarTests
+    {
+        [Test]
+        public void TestAssignmentUnchanged()
+        {
+            var intVar = new NetworkVariable<int>();
+
+            intVar.Value = 314159265;
+
+            intVar.OnValueChanged += (value, newValue) =>
+            {
+                Assert.Fail("OnValueChanged was invoked when setting the same value");
+            };
+
+            intVar.Value = 314159265;
+        }
+
+        [Test]
+        public void TestAssignmentChanged()
+        {
+            var intVar = new NetworkVariable<int>();
+
+            intVar.Value = 314159265;
+
+            var changed = false;
+
+            intVar.OnValueChanged += (value, newValue) =>
+            {
+                changed = true;
+            };
+
+            intVar.Value = 314159266;
+
+            Assert.True(changed);
+        }
+    }
+}

Tests/Editor/NetworkVar/NetworkVarTests.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: a7cdd8c1251f4352b1f1d4825dc85182
+timeCreated: 1647861669

Tests/Editor/Serialization/FastBufferReaderTests.cs

@@ -393,6 +393,34 @@ namespace Unity.Netcode.EditorTests
             }
         }
 
+        [Test]
+        public void WhenCreatingNewFastBufferReader_IsInitializedIsTrue()
+        {
+            var array = new NativeArray<byte>(100, Allocator.Temp);
+            var reader = new FastBufferReader(array, Allocator.Temp);
+            Assert.AreEqual(true, reader.IsInitialized);
+            reader.Dispose();
+            array.Dispose();
+        }
+
+        [Test]
+        public void WhenDisposingFastBufferReader_IsInitializedIsFalse()
+        {
+            var array = new NativeArray<byte>(100, Allocator.Temp);
+            var reader = new FastBufferReader(array, Allocator.Temp);
+            reader.Dispose();
+            Assert.AreEqual(false, reader.IsInitialized);
+            array.Dispose();
+            Assert.AreEqual(false, reader.IsInitialized);
+        }
+
+        [Test]
+        public void WhenUsingDefaultFastBufferReader_IsInitializedIsFalse()
+        {
+            FastBufferReader writer = default;
+            Assert.AreEqual(false, writer.IsInitialized);
+        }
+
         [Test]
         public void WhenCallingReadByteWithoutCallingTryBeingReadFirst_OverflowExceptionIsThrown()
         {

Tests/Editor/Serialization/FastBufferWriterTests.cs

@@ -891,6 +891,29 @@ namespace Unity.Netcode.EditorTests
             writer.Dispose();
         }
 
+        [Test]
+        public void WhenCreatingNewFastBufferWriter_IsInitializedIsTrue()
+        {
+            var writer = new FastBufferWriter(100, Allocator.Temp);
+            Assert.AreEqual(true, writer.IsInitialized);
+            writer.Dispose();
+        }
+
+        [Test]
+        public void WhenDisposingFastBufferWriter_IsInitializedIsFalse()
+        {
+            var writer = new FastBufferWriter(100, Allocator.Temp);
+            writer.Dispose();
+            Assert.AreEqual(false, writer.IsInitialized);
+        }
+
+        [Test]
+        public void WhenUsingDefaultFastBufferWriter_IsInitializedIsFalse()
+        {
+            FastBufferWriter writer = default;
+            Assert.AreEqual(false, writer.IsInitialized);
+        }
+
         [Test]
         public void WhenRequestingWritePastBoundsForNonGrowingWriter_TryBeginWriteReturnsFalse()
         {

Tests/Editor/SnapshotRttTests.cs

@@ -1,73 +0,0 @@
-using NUnit.Framework;
-
-namespace Unity.Netcode.EditorTests
-{
-    public class SnapshotRttTests
-    {
-        private const double k_Epsilon = 0.0001;
-
-        [Test]
-        public void TestBasicRtt()
-        {
-            var snapshot = new SnapshotSystem(null, new NetworkConfig(), null);
-            var client1 = snapshot.GetConnectionRtt(0);
-
-            client1.NotifySend(0, 0.0);
-            client1.NotifySend(1, 10.0);
-
-            client1.NotifyAck(1, 15.0);
-
-            client1.NotifySend(2, 20.0);
-            client1.NotifySend(3, 30.0);
-            client1.NotifySend(4, 32.0);
-
-            client1.NotifyAck(4, 38.0);
-            client1.NotifyAck(3, 40.0);
-
-            ConnectionRtt.Rtt ret = client1.GetRtt();
-            Assert.True(ret.AverageSec < 7.0 + k_Epsilon);
-            Assert.True(ret.AverageSec > 7.0 - k_Epsilon);
-            Assert.True(ret.WorstSec < 10.0 + k_Epsilon);
-            Assert.True(ret.WorstSec > 10.0 - k_Epsilon);
-            Assert.True(ret.BestSec < 5.0 + k_Epsilon);
-            Assert.True(ret.BestSec > 5.0 - k_Epsilon);
-
-            // note: `last` latency is latest received Ack, not latest sent sequence.
-            Assert.True(ret.LastSec < 10.0 + k_Epsilon);
-            Assert.True(ret.LastSec > 10.0 - k_Epsilon);
-        }
-
-        [Test]
-        public void TestEdgeCasesRtt()
-        {
-            var snapshot = new SnapshotSystem(null, new NetworkConfig(), null);
-            var client1 = snapshot.GetConnectionRtt(0);
-            var iterationCount = NetworkConfig.RttWindowSize * 3;
-            var extraCount = NetworkConfig.RttWindowSize * 2;
-
-            // feed in some messages
-            for (var iteration = 0; iteration < iterationCount; iteration++)
-            {
-                client1.NotifySend(iteration, 25.0 * iteration);
-            }
-            // ack some random ones in there (1 out of each 9), always 7.0 later
-            for (var iteration = 0; iteration < iterationCount; iteration += 9)
-            {
-                client1.NotifyAck(iteration, 25.0 * iteration + 7.0);
-            }
-            // ack some unused key, to check it doesn't throw off the values
-            for (var iteration = iterationCount; iteration < iterationCount + extraCount; iteration++)
-            {
-                client1.NotifyAck(iteration, 42.0);
-            }
-
-            ConnectionRtt.Rtt ret = client1.GetRtt();
-            Assert.True(ret.AverageSec < 7.0 + k_Epsilon);
-            Assert.True(ret.AverageSec > 7.0 - k_Epsilon);
-            Assert.True(ret.WorstSec < 7.0 + k_Epsilon);
-            Assert.True(ret.WorstSec > 7.0 - k_Epsilon);
-            Assert.True(ret.BestSec < 7.0 + k_Epsilon);
-            Assert.True(ret.BestSec > 7.0 - k_Epsilon);
-        }
-    }
-}

Tests/Editor/SnapshotRttTests.cs.meta

@@ -1,11 +0,0 @@
-fileFormatVersion: 2
-guid: a05afab7f08d44c07b2c5e144ba0b45a
-MonoImporter:
-  externalObjects: {}
-  serializedVersion: 2
-  defaultReferences: []
-  executionOrder: 0
-  icon: {instanceID: 0}
-  userData: 
-  assetBundleName: 
-  assetBundleVariant: 

Tests/Editor/SnapshotTests.cs

@@ -1,363 +0,0 @@
-using System;
-using System.Collections.Generic;
-using Unity.Collections;
-using UnityEngine;
-using NUnit.Framework;
-using Random = System.Random;
-
-namespace Unity.Netcode.EditorTests
-{
-    public class SnapshotTests
-    {
-        private SnapshotSystem m_SendSnapshot;
-        private SnapshotSystem m_RecvSnapshot;
-
-        private NetworkTimeSystem m_SendTimeSystem;
-        private NetworkTickSystem m_SendTickSystem;
-        private NetworkTimeSystem m_RecvTimeSystem;
-        private NetworkTickSystem m_RecvTickSystem;
-
-        private int m_SpawnedObjectCount;
-        private int m_DespawnedObjectCount;
-        private int m_NextSequence;
-        private uint m_TicksPerSec = 15;
-        private int m_MinSpawns;
-        private int m_MinDespawns;
-
-        private bool m_ExpectSpawns;
-        private bool m_ExpectDespawns;
-        private bool m_LoseNextMessage;
-        private bool m_PassBackResponses;
-
-        public void Prepare()
-        {
-            PrepareSendSideSnapshot();
-            PrepareRecvSideSnapshot();
-        }
-
-        public void AdvanceOneTickSendSide()
-        {
-            m_SendTimeSystem.Advance(1.0f / m_TicksPerSec);
-            m_SendTickSystem.UpdateTick(m_SendTimeSystem.LocalTime, m_SendTimeSystem.ServerTime);
-            m_SendSnapshot.NetworkUpdate(NetworkUpdateStage.EarlyUpdate);
-        }
-
-        public void AdvanceOneTickRecvSide()
-        {
-            m_RecvTimeSystem.Advance(1.0f / m_TicksPerSec);
-            m_RecvTickSystem.UpdateTick(m_RecvTimeSystem.LocalTime, m_RecvTimeSystem.ServerTime);
-            m_RecvSnapshot.NetworkUpdate(NetworkUpdateStage.EarlyUpdate);
-        }
-
-        public void AdvanceOneTick()
-        {
-            AdvanceOneTickSendSide();
-            AdvanceOneTickRecvSide();
-        }
-
-        internal int SpawnObject(SnapshotSpawnCommand command)
-        {
-            m_SpawnedObjectCount++;
-            return 0;
-        }
-
-        internal int DespawnObject(SnapshotDespawnCommand command)
-        {
-            m_DespawnedObjectCount++;
-            return 0;
-        }
-
-        internal int SendMessage(ref SnapshotDataMessage message, NetworkDelivery delivery, ulong clientId)
-        {
-            if (!m_PassBackResponses)
-            {
-                // we're not ack'ing anything, so those should stay 0
-                Debug.Assert(message.Ack.LastReceivedSequence == 0);
-            }
-
-            Debug.Assert(message.Ack.ReceivedSequenceMask == 0);
-            Debug.Assert(message.Sequence == m_NextSequence); // sequence has to be the expected one
-
-            if (m_ExpectSpawns)
-            {
-                Debug.Assert(message.Spawns.Length >= m_MinSpawns); // there has to be multiple spawns per SnapshotMessage
-            }
-            else
-            {
-                Debug.Assert(message.Spawns.Length == 0); // Spawns were not expected
-            }
-
-            if (m_ExpectDespawns)
-            {
-                Debug.Assert(message.Despawns.Length >= m_MinDespawns); // there has to be multiple despawns per SnapshotMessage
-            }
-            else
-            {
-                Debug.Assert(message.Despawns.IsEmpty); // this test should not have despawns
-            }
-
-            Debug.Assert(message.Entries.Length == 0);
-
-            m_NextSequence++;
-
-            if (!m_LoseNextMessage)
-            {
-                using var writer = new FastBufferWriter(1024, Allocator.Temp);
-                message.Serialize(writer);
-                using var reader = new FastBufferReader(writer, Allocator.Temp);
-                var context = new NetworkContext { SenderId = 0, Timestamp = 0.0f, SystemOwner = new Tuple<SnapshotSystem, ulong>(m_RecvSnapshot, 0) };
-                var newMessage = new SnapshotDataMessage();
-                newMessage.Deserialize(reader, ref context);
-                newMessage.Handle(ref context);
-            }
-
-            return 0;
-        }
-
-        internal int SendMessageRecvSide(ref SnapshotDataMessage message, NetworkDelivery delivery, ulong clientId)
-        {
-            if (m_PassBackResponses)
-            {
-                using var writer = new FastBufferWriter(1024, Allocator.Temp);
-                message.Serialize(writer);
-                using var reader = new FastBufferReader(writer, Allocator.Temp);
-                var context = new NetworkContext { SenderId = 0, Timestamp = 0.0f, SystemOwner = new Tuple<SnapshotSystem, ulong>(m_SendSnapshot, 1) };
-                var newMessage = new SnapshotDataMessage();
-                newMessage.Deserialize(reader, ref context);
-                newMessage.Handle(ref context);
-            }
-
-            return 0;
-        }
-
-
-        private void PrepareSendSideSnapshot()
-        {
-            var config = new NetworkConfig();
-
-            m_SendTickSystem = new NetworkTickSystem(m_TicksPerSec, 0.0, 0.0);
-            m_SendTimeSystem = new NetworkTimeSystem(0.2, 0.2, 1.0);
-
-            config.UseSnapshotDelta = false;
-            config.UseSnapshotSpawn = true;
-
-            m_SendSnapshot = new SnapshotSystem(null, config, m_SendTickSystem);
-
-            m_SendSnapshot.IsServer = true;
-            m_SendSnapshot.IsConnectedClient = false;
-            m_SendSnapshot.ServerClientId = 0;
-            m_SendSnapshot.ConnectedClientsId.Clear();
-            m_SendSnapshot.ConnectedClientsId.Add(0);
-            m_SendSnapshot.ConnectedClientsId.Add(1);
-            m_SendSnapshot.MockSendMessage = SendMessage;
-            m_SendSnapshot.MockSpawnObject = SpawnObject;
-            m_SendSnapshot.MockDespawnObject = DespawnObject;
-        }
-
-        private void PrepareRecvSideSnapshot()
-        {
-            var config = new NetworkConfig();
-
-            m_RecvTickSystem = new NetworkTickSystem(m_TicksPerSec, 0.0, 0.0);
-            m_RecvTimeSystem = new NetworkTimeSystem(0.2, 0.2, 1.0);
-
-            config.UseSnapshotDelta = false;
-            config.UseSnapshotSpawn = true;
-
-            m_RecvSnapshot = new SnapshotSystem(null, config, m_RecvTickSystem);
-
-            m_RecvSnapshot.IsServer = false;
-            m_RecvSnapshot.IsConnectedClient = true;
-            m_RecvSnapshot.ServerClientId = 0;
-            m_RecvSnapshot.ConnectedClientsId.Clear();
-            m_SendSnapshot.ConnectedClientsId.Add(0);
-            m_SendSnapshot.ConnectedClientsId.Add(1);
-            m_RecvSnapshot.MockSendMessage = SendMessageRecvSide;
-            m_RecvSnapshot.MockSpawnObject = SpawnObject;
-            m_RecvSnapshot.MockDespawnObject = DespawnObject;
-        }
-
-        private void SendSpawnToSnapshot(ulong objectId)
-        {
-            SnapshotSpawnCommand command = default;
-            // identity
-            command.NetworkObjectId = objectId;
-            // archetype
-            command.GlobalObjectIdHash = 0;
-            command.IsSceneObject = true;
-            // parameters
-            command.IsPlayerObject = false;
-            command.OwnerClientId = 0;
-            command.ParentNetworkId = 0;
-            command.ObjectPosition = default;
-            command.ObjectRotation = default;
-            command.ObjectScale = new Vector3(1.0f, 1.0f, 1.0f);
-            command.TargetClientIds = new List<ulong> { 1 };
-            m_SendSnapshot.Spawn(command);
-        }
-
-        private void SendDespawnToSnapshot(ulong objectId)
-        {
-            SnapshotDespawnCommand command = default;
-            // identity
-            command.NetworkObjectId = objectId;
-            command.TargetClientIds = new List<ulong> { 1 };
-            m_SendSnapshot.Despawn(command);
-        }
-
-        [Test]
-        public void TestSnapshotSpawn()
-        {
-            Prepare();
-
-            m_SpawnedObjectCount = 0;
-            m_NextSequence = 0;
-            m_ExpectSpawns = true;
-            m_ExpectDespawns = false;
-            m_MinSpawns = 2; // many spawns are to be sent together
-            m_LoseNextMessage = false;
-            m_PassBackResponses = false;
-
-            var ticksToRun = 20;
-
-            // spawns one more than current buffer size
-            var objectsToSpawn = m_SendSnapshot.SpawnsBufferCount + 1;
-
-            for (int i = 0; i < objectsToSpawn; i++)
-            {
-                SendSpawnToSnapshot((ulong)i);
-            }
-
-            for (int i = 0; i < ticksToRun; i++)
-            {
-                AdvanceOneTick();
-            }
-
-            Debug.Assert(m_SpawnedObjectCount == objectsToSpawn);
-            Debug.Assert(m_SendSnapshot.SpawnsBufferCount > objectsToSpawn); // spawn buffer should have grown
-        }
-
-        [Test]
-        public void TestSnapshotSpawnDespawns()
-        {
-            Prepare();
-
-            // test that buffers actually shrink and will grow back to needed size
-            m_SendSnapshot.ReduceBufferUsage();
-            m_RecvSnapshot.ReduceBufferUsage();
-            Debug.Assert(m_SendSnapshot.SpawnsBufferCount == 1);
-            Debug.Assert(m_SendSnapshot.DespawnsBufferCount == 1);
-            Debug.Assert(m_RecvSnapshot.SpawnsBufferCount == 1);
-            Debug.Assert(m_RecvSnapshot.DespawnsBufferCount == 1);
-
-            m_SpawnedObjectCount = 0;
-            m_DespawnedObjectCount = 0;
-
-            m_NextSequence = 0;
-            m_ExpectSpawns = true;
-            m_ExpectDespawns = false;
-            m_MinDespawns = 2; // many despawns are to be sent together
-            m_LoseNextMessage = false;
-            m_PassBackResponses = false;
-
-            var ticksToRun = 20;
-
-            // spawns one more than current buffer size
-            var objectsToSpawn = 10;
-
-            for (int i = 0; i < objectsToSpawn; i++)
-            {
-                SendSpawnToSnapshot((ulong)i);
-            }
-
-            for (int i = 0; i < ticksToRun; i++)
-            {
-                AdvanceOneTick();
-            }
-
-            for (int i = 0; i < objectsToSpawn; i++)
-            {
-                SendDespawnToSnapshot((ulong)i);
-            }
-
-            m_ExpectSpawns = true; // the un'acked spawns will still be present
-            m_MinSpawns = 1; // but we don't really care how they are grouped then
-            m_ExpectDespawns = true;
-
-            for (int i = 0; i < ticksToRun; i++)
-            {
-                AdvanceOneTick();
-            }
-
-            Debug.Assert(m_DespawnedObjectCount == objectsToSpawn);
-        }
-
-        [Test]
-        public void TestSnapshotMessageLoss()
-        {
-            var r = new Random();
-            Prepare();
-
-            m_SpawnedObjectCount = 0;
-            m_NextSequence = 0;
-            m_ExpectSpawns = true;
-            m_ExpectDespawns = false;
-            m_MinSpawns = 1;
-            m_LoseNextMessage = false;
-            m_PassBackResponses = false;
-
-            var ticksToRun = 10;
-
-            for (int i = 0; i < ticksToRun; i++)
-            {
-                m_LoseNextMessage = (r.Next() % 2) > 0;
-
-                SendSpawnToSnapshot((ulong)i);
-                AdvanceOneTick();
-            }
-
-            m_LoseNextMessage = false;
-            AdvanceOneTick();
-            AdvanceOneTick();
-
-            Debug.Assert(m_SpawnedObjectCount == ticksToRun);
-        }
-
-        [Test]
-        public void TestSnapshotAcks()
-        {
-            Prepare();
-
-            m_SpawnedObjectCount = 0;
-            m_NextSequence = 0;
-            m_ExpectSpawns = true;
-            m_ExpectDespawns = false;
-            m_MinSpawns = 1;
-            m_LoseNextMessage = false;
-            m_PassBackResponses = true;
-
-            var objectsToSpawn = 10;
-
-            for (int i = 0; i < objectsToSpawn; i++)
-            {
-                SendSpawnToSnapshot((ulong)i);
-            }
-            AdvanceOneTickSendSide(); // let's tick the send multiple time, to check it still tries to send
-            AdvanceOneTick();
-
-            m_ExpectSpawns = false; // all spawns should have made it back and forth and be absent from next messages
-            AdvanceOneTick();
-
-            for (int i = 0; i < objectsToSpawn; i++)
-            {
-                SendDespawnToSnapshot((ulong)i);
-            }
-
-            m_ExpectDespawns = true; // we should now be seeing despawns
-            AdvanceOneTickSendSide(); // let's tick the send multiple time, to check it still tries to send
-            AdvanceOneTick();
-
-            Debug.Assert(m_SpawnedObjectCount == objectsToSpawn);
-        }
-    }
-}

Tests/Editor/SnapshotTests.cs.meta

@@ -1,11 +0,0 @@
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-MonoImporter:
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-  serializedVersion: 2
-  defaultReferences: []
-  executionOrder: 0
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-  userData: 
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-  assetBundleVariant: 

Tests/Editor/Transports.meta

@@ -0,0 +1,8 @@
+fileFormatVersion: 2
+guid: f4ecf3bb8c5654c1aae7f73d21e8c56e
+folderAsset: yes
+DefaultImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Tests/Editor/Transports/BatchedReceiveQueueTests.cs

@@ -0,0 +1,193 @@
+using System;
+using NUnit.Framework;
+using Unity.Collections;
+using Unity.Netcode.Transports.UTP;
+using Unity.Networking.Transport;
+
+namespace Unity.Netcode.EditorTests
+{
+    public class BatchedReceiveQueueTests
+    {
+        [Test]
+        public void BatchedReceiveQueue_EmptyReader()
+        {
+            var data = new NativeArray<byte>(0, Allocator.Temp);
+
+            var reader = new DataStreamReader(data);
+            var q = new BatchedReceiveQueue(reader);
+            Assert.AreEqual(default(ArraySegment<byte>), q.PopMessage());
+            Assert.True(q.IsEmpty);
+        }
+
+        [Test]
+        public void BatchedReceiveQueue_SingleMessage()
+        {
+            var dataLength = sizeof(int) + 1;
+
+            var data = new NativeArray<byte>(dataLength, Allocator.Temp);
+
+            var writer = new DataStreamWriter(data);
+            writer.WriteInt(1);
+            writer.WriteByte((byte)42);
+
+            var reader = new DataStreamReader(data);
+            var q = new BatchedReceiveQueue(reader);
+
+            Assert.False(q.IsEmpty);
+
+            var message = q.PopMessage();
+            Assert.AreEqual(1, message.Count);
+            Assert.AreEqual((byte)42, message.Array[message.Offset]);
+
+            Assert.AreEqual(default(ArraySegment<byte>), q.PopMessage());
+            Assert.True(q.IsEmpty);
+        }
+
+        [Test]
+        public void BatchedReceiveQueue_MultipleMessages()
+        {
+            var dataLength = (sizeof(int) + 1) * 2;
+
+            var data = new NativeArray<byte>(dataLength, Allocator.Temp);
+
+            var writer = new DataStreamWriter(data);
+            writer.WriteInt(1);
+            writer.WriteByte((byte)42);
+            writer.WriteInt(1);
+            writer.WriteByte((byte)142);
+
+            var reader = new DataStreamReader(data);
+            var q = new BatchedReceiveQueue(reader);
+
+            Assert.False(q.IsEmpty);
+
+            var message1 = q.PopMessage();
+            Assert.AreEqual(1, message1.Count);
+            Assert.AreEqual((byte)42, message1.Array[message1.Offset]);
+
+            var message2 = q.PopMessage();
+            Assert.AreEqual(1, message2.Count);
+            Assert.AreEqual((byte)142, message2.Array[message2.Offset]);
+
+            Assert.AreEqual(default(ArraySegment<byte>), q.PopMessage());
+            Assert.True(q.IsEmpty);
+        }
+
+        [Test]
+        public void BatchedReceiveQueue_PartialMessage()
+        {
+            var dataLength = sizeof(int);
+
+            var data = new NativeArray<byte>(dataLength, Allocator.Temp);
+
+            var writer = new DataStreamWriter(data);
+            writer.WriteInt(42);
+
+            var reader = new DataStreamReader(data);
+            var q = new BatchedReceiveQueue(reader);
+
+            Assert.False(q.IsEmpty);
+            Assert.AreEqual(default(ArraySegment<byte>), q.PopMessage());
+        }
+
+        [Test]
+        public void BatchedReceiveQueue_PushReader_ToFilledQueue()
+        {
+            var data1Length = sizeof(int);
+            var data2Length = sizeof(byte);
+
+            var data1 = new NativeArray<byte>(data1Length, Allocator.Temp);
+            var data2 = new NativeArray<byte>(data2Length, Allocator.Temp);
+
+            var writer1 = new DataStreamWriter(data1);
+            writer1.WriteInt(1);
+            var writer2 = new DataStreamWriter(data2);
+            writer2.WriteByte(42);
+
+            var reader1 = new DataStreamReader(data1);
+            var reader2 = new DataStreamReader(data2);
+
+            var q = new BatchedReceiveQueue(reader1);
+
+            Assert.False(q.IsEmpty);
+
+            q.PushReader(reader2);
+
+            Assert.False(q.IsEmpty);
+
+            var message = q.PopMessage();
+            Assert.AreEqual(1, message.Count);
+            Assert.AreEqual((byte)42, message.Array[message.Offset]);
+
+            Assert.AreEqual(default(ArraySegment<byte>), q.PopMessage());
+            Assert.True(q.IsEmpty);
+        }
+
+        [Test]
+        public void BatchedReceiveQueue_PushReader_ToPartiallyFilledQueue()
+        {
+            var dataLength = sizeof(int) + 1;
+
+            var data = new NativeArray<byte>(dataLength, Allocator.Temp);
+
+            var writer = new DataStreamWriter(data);
+            writer.WriteInt(1);
+            writer.WriteByte((byte)42);
+
+            var reader = new DataStreamReader(data);
+            var q = new BatchedReceiveQueue(reader);
+
+            reader = new DataStreamReader(data);
+            q.PushReader(reader);
+
+            var message = q.PopMessage();
+            Assert.AreEqual(1, message.Count);
+            Assert.AreEqual((byte)42, message.Array[message.Offset]);
+
+            reader = new DataStreamReader(data);
+            q.PushReader(reader);
+
+            message = q.PopMessage();
+            Assert.AreEqual(1, message.Count);
+            Assert.AreEqual((byte)42, message.Array[message.Offset]);
+
+            message = q.PopMessage();
+            Assert.AreEqual(1, message.Count);
+            Assert.AreEqual((byte)42, message.Array[message.Offset]);
+
+            Assert.AreEqual(default(ArraySegment<byte>), q.PopMessage());
+            Assert.True(q.IsEmpty);
+        }
+
+        [Test]
+        public void BatchedReceiveQueue_PushReader_ToEmptyQueue()
+        {
+            var dataLength = sizeof(int) + 1;
+
+            var data = new NativeArray<byte>(dataLength, Allocator.Temp);
+
+            var writer = new DataStreamWriter(data);
+            writer.WriteInt(1);
+            writer.WriteByte((byte)42);
+
+            var reader = new DataStreamReader(data);
+            var q = new BatchedReceiveQueue(reader);
+
+            Assert.False(q.IsEmpty);
+
+            q.PopMessage();
+
+            Assert.True(q.IsEmpty);
+
+            reader = new DataStreamReader(data);
+            q.PushReader(reader);
+
+            var message = q.PopMessage();
+            Assert.AreEqual(1, message.Count);
+            Assert.AreEqual((byte)42, message.Array[message.Offset]);
+
+            Assert.AreEqual(default(ArraySegment<byte>), q.PopMessage());
+            Assert.True(q.IsEmpty);
+        }
+    }
+}

Tests/Editor/Transports/BatchedReceiveQueueTests.cs.meta

@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: aabb21b30a80142ea86e59d1b4d5c587
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Tests/Editor/Transports/BatchedSendQueueTests.cs

@@ -0,0 +1,266 @@
+using System;
+using NUnit.Framework;
+using Unity.Collections;
+using Unity.Netcode.Transports.UTP;
+using Unity.Networking.Transport;
+
+namespace Unity.Netcode.EditorTests
+{
+    public class BatchedSendQueueTests
+    {
+        private const int k_TestQueueCapacity = 1024;
+        private const int k_TestMessageSize = 42;
+
+        private ArraySegment<byte> m_TestMessage;
+
+        private void AssertIsTestMessage(NativeArray<byte> data)
+        {
+            var reader = new DataStreamReader(data);
+            Assert.AreEqual(k_TestMessageSize, reader.ReadInt());
+            for (int i = 0; i < k_TestMessageSize; i++)
+            {
+                Assert.AreEqual(m_TestMessage.Array[i], reader.ReadByte());
+            }
+        }
+
+        [OneTimeSetUp]
+        public void InitializeTestMessage()
+        {
+            var data = new byte[k_TestMessageSize];
+            for (int i = 0; i < k_TestMessageSize; i++)
+            {
+                data[i] = (byte)i;
+            }
+            m_TestMessage = new ArraySegment<byte>(data);
+        }
+
+        [Test]
+        public void BatchedSendQueue_EmptyOnCreation()
+        {
+            using var q = new BatchedSendQueue(k_TestQueueCapacity);
+
+            Assert.AreEqual(0, q.Length);
+            Assert.True(q.IsEmpty);
+        }
+
+        [Test]
+        public void BatchedSendQueue_NotCreatedAfterDispose()
+        {
+            var q = new BatchedSendQueue(k_TestQueueCapacity);
+            q.Dispose();
+            Assert.False(q.IsCreated);
+        }
+
+        [Test]
+        public void BatchedSendQueue_PushMessageReturnValue()
+        {
+            // Will fit a single test message, but not two (with overhead included).
+            var queueCapacity = (k_TestMessageSize * 2) + BatchedSendQueue.PerMessageOverhead;
+
+            using var q = new BatchedSendQueue(queueCapacity);
+
+            Assert.True(q.PushMessage(m_TestMessage));
+            Assert.False(q.PushMessage(m_TestMessage));
+        }
+
+        [Test]
+        public void BatchedSendQueue_LengthIncreasedAfterPush()
+        {
+            using var q = new BatchedSendQueue(k_TestQueueCapacity);
+
+            q.PushMessage(m_TestMessage);
+            Assert.AreEqual(k_TestMessageSize + BatchedSendQueue.PerMessageOverhead, q.Length);
+        }
+
+        [Test]
+        public void BatchedSendQueue_PushedMessageGeneratesCopy()
+        {
+            var messageLength = k_TestMessageSize + BatchedSendQueue.PerMessageOverhead;
+            var queueCapacity = messageLength * 2;
+
+            using var q = new BatchedSendQueue(queueCapacity);
+            using var data = new NativeArray<byte>(k_TestQueueCapacity, Allocator.Temp);
+
+            q.PushMessage(m_TestMessage);
+            q.PushMessage(m_TestMessage);
+
+            q.Consume(messageLength);
+            Assert.IsTrue(q.PushMessage(m_TestMessage));
+            Assert.AreEqual(queueCapacity, q.Length);
+        }
+
+        [Test]
+        public void BatchedSendQueue_FillWriterWithMessages_ReturnValue()
+        {
+            using var q = new BatchedSendQueue(k_TestQueueCapacity);
+            using var data = new NativeArray<byte>(k_TestQueueCapacity, Allocator.Temp);
+
+            q.PushMessage(m_TestMessage);
+
+            var writer = new DataStreamWriter(data);
+            var filled = q.FillWriterWithMessages(ref writer);
+            Assert.AreEqual(k_TestMessageSize + BatchedSendQueue.PerMessageOverhead, filled);
+        }
+
+        [Test]
+        public void BatchedSendQueue_FillWriterWithMessages_NoopIfNoPushedMessages()
+        {
+            using var q = new BatchedSendQueue(k_TestQueueCapacity);
+            using var data = new NativeArray<byte>(k_TestQueueCapacity, Allocator.Temp);
+
+            var writer = new DataStreamWriter(data);
+            Assert.AreEqual(0, q.FillWriterWithMessages(ref writer));
+        }
+
+        [Test]
+        public void BatchedSendQueue_FillWriterWithMessages_NoopIfNotEnoughCapacity()
+        {
+            using var q = new BatchedSendQueue(k_TestQueueCapacity);
+            using var data = new NativeArray<byte>(2, Allocator.Temp);
+
+            q.PushMessage(m_TestMessage);
+
+            var writer = new DataStreamWriter(data);
+            Assert.AreEqual(0, q.FillWriterWithMessages(ref writer));
+        }
+
+        [Test]
+        public void BatchedSendQueue_FillWriterWithMessages_SinglePushedMessage()
+        {
+            using var q = new BatchedSendQueue(k_TestQueueCapacity);
+            using var data = new NativeArray<byte>(k_TestQueueCapacity, Allocator.Temp);
+
+            q.PushMessage(m_TestMessage);
+
+            var writer = new DataStreamWriter(data);
+            q.FillWriterWithMessages(ref writer);
+            AssertIsTestMessage(data);
+        }
+
+        [Test]
+        public void BatchedSendQueue_FillWriterWithMessages_MultiplePushedMessages()
+        {
+            using var q = new BatchedSendQueue(k_TestQueueCapacity);
+            using var data = new NativeArray<byte>(k_TestQueueCapacity, Allocator.Temp);
+
+            q.PushMessage(m_TestMessage);
+            q.PushMessage(m_TestMessage);
+
+            var writer = new DataStreamWriter(data);
+            q.FillWriterWithMessages(ref writer);
+
+            var messageLength = k_TestMessageSize + BatchedSendQueue.PerMessageOverhead;
+            AssertIsTestMessage(data);
+            AssertIsTestMessage(data.GetSubArray(messageLength, messageLength));
+        }
+
+        [Test]
+        public void BatchedSendQueue_FillWriterWithMessages_PartialPushedMessages()
+        {
+            var messageLength = k_TestMessageSize + BatchedSendQueue.PerMessageOverhead;
+
+            using var q = new BatchedSendQueue(k_TestQueueCapacity);
+            using var data = new NativeArray<byte>(messageLength, Allocator.Temp);
+
+            q.PushMessage(m_TestMessage);
+            q.PushMessage(m_TestMessage);
+
+            var writer = new DataStreamWriter(data);
+            Assert.AreEqual(messageLength, q.FillWriterWithMessages(ref writer));
+            AssertIsTestMessage(data);
+        }
+
+        [Test]
+        public void BatchedSendQueue_FillWriterWithBytes_NoopIfNoData()
+        {
+            using var q = new BatchedSendQueue(k_TestQueueCapacity);
+            using var data = new NativeArray<byte>(k_TestQueueCapacity, Allocator.Temp);
+
+            var writer = new DataStreamWriter(data);
+            Assert.AreEqual(0, q.FillWriterWithBytes(ref writer));
+        }
+
+        [Test]
+        public void BatchedSendQueue_FillWriterWithBytes_WriterCapacityMoreThanLength()
+        {
+            var dataLength = k_TestMessageSize + BatchedSendQueue.PerMessageOverhead;
+
+            using var q = new BatchedSendQueue(k_TestQueueCapacity);
+            using var data = new NativeArray<byte>(k_TestQueueCapacity, Allocator.Temp);
+
+            q.PushMessage(m_TestMessage);
+
+            var writer = new DataStreamWriter(data);
+            Assert.AreEqual(dataLength, q.FillWriterWithBytes(ref writer));
+            AssertIsTestMessage(data);
+        }
+
+        [Test]
+        public void BatchedSendQueue_FillWriterWithBytes_WriterCapacityLessThanLength()
+        {
+            var dataLength = k_TestMessageSize + BatchedSendQueue.PerMessageOverhead;
+
+            using var q = new BatchedSendQueue(k_TestQueueCapacity);
+            using var data = new NativeArray<byte>(dataLength, Allocator.Temp);
+
+            q.PushMessage(m_TestMessage);
+            q.PushMessage(m_TestMessage);
+
+            var writer = new DataStreamWriter(data);
+            Assert.AreEqual(dataLength, q.FillWriterWithBytes(ref writer));
+            AssertIsTestMessage(data);
+        }
+
+        [Test]
+        public void BatchedSendQueue_FillWriterWithBytes_WriterCapacityEqualToLength()
+        {
+            var dataLength = k_TestMessageSize + BatchedSendQueue.PerMessageOverhead;
+
+            using var q = new BatchedSendQueue(k_TestQueueCapacity);
+            using var data = new NativeArray<byte>(dataLength, Allocator.Temp);
+
+            q.PushMessage(m_TestMessage);
+
+            var writer = new DataStreamWriter(data);
+            Assert.AreEqual(dataLength, q.FillWriterWithBytes(ref writer));
+            AssertIsTestMessage(data);
+        }
+
+        [Test]
+        public void BatchedSendQueue_ConsumeLessThanLength()
+        {
+            using var q = new BatchedSendQueue(k_TestQueueCapacity);
+
+            q.PushMessage(m_TestMessage);
+            q.PushMessage(m_TestMessage);
+
+            var messageLength = k_TestMessageSize + BatchedSendQueue.PerMessageOverhead;
+            q.Consume(messageLength);
+            Assert.AreEqual(messageLength, q.Length);
+        }
+
+        [Test]
+        public void BatchedSendQueue_ConsumeExactLength()
+        {
+            using var q = new BatchedSendQueue(k_TestQueueCapacity);
+
+            q.PushMessage(m_TestMessage);
+
+            q.Consume(k_TestMessageSize + BatchedSendQueue.PerMessageOverhead);
+            Assert.AreEqual(0, q.Length);
+            Assert.True(q.IsEmpty);
+        }
+
+        [Test]
+        public void BatchedSendQueue_ConsumeMoreThanLength()
+        {
+            using var q = new BatchedSendQueue(k_TestQueueCapacity);
+
+            q.PushMessage(m_TestMessage);
+
+            q.Consume(k_TestQueueCapacity);
+            Assert.AreEqual(0, q.Length);
+            Assert.True(q.IsEmpty);
+        }
+    }
+}

Tests/Editor/Transports/BatchedSendQueueTests.cs.meta

@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 51a68dc80bf18443180f3600eb5890d7
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Tests/Editor/Transports/UnityTransportTests.cs

@@ -0,0 +1,84 @@
+using NUnit.Framework;
+using Unity.Netcode.Transports.UTP;
+using UnityEngine;
+
+namespace Unity.Netcode.EditorTests
+{
+    public class UnityTransportTests
+    {
+        // Check that starting a server doesn't immediately result in faulted tasks.
+        [Test]
+        public void BasicInitServer()
+        {
+            UnityTransport transport = new GameObject().AddComponent<UnityTransport>();
+            transport.Initialize();
+
+            Assert.True(transport.StartServer());
+
+            transport.Shutdown();
+        }
+
+        // Check that starting a client doesn't immediately result in faulted tasks.
+        [Test]
+        public void BasicInitClient()
+        {
+            UnityTransport transport = new GameObject().AddComponent<UnityTransport>();
+            transport.Initialize();
+
+            Assert.True(transport.StartClient());
+
+            transport.Shutdown();
+        }
+
+        // Check that we can't restart a server.
+        [Test]
+        public void NoRestartServer()
+        {
+            UnityTransport transport = new GameObject().AddComponent<UnityTransport>();
+            transport.Initialize();
+
+            transport.StartServer();
+            Assert.False(transport.StartServer());
+
+            transport.Shutdown();
+        }
+
+        // Check that we can't restart a client.
+        [Test]
+        public void NoRestartClient()
+        {
+            UnityTransport transport = new GameObject().AddComponent<UnityTransport>();
+            transport.Initialize();
+
+            transport.StartClient();
+            Assert.False(transport.StartClient());
+
+            transport.Shutdown();
+        }
+
+        // Check that we can't start both a server and client on the same transport.
+        [Test]
+        public void NotBothServerAndClient()
+        {
+            UnityTransport transport;
+
+            // Start server then client.
+            transport = new GameObject().AddComponent<UnityTransport>();
+            transport.Initialize();
+
+            transport.StartServer();
+            Assert.False(transport.StartClient());
+
+            transport.Shutdown();
+
+            // Start client then server.
+            transport = new GameObject().AddComponent<UnityTransport>();
+            transport.Initialize();
+
+            transport.StartClient();
+            Assert.False(transport.StartServer());
+
+            transport.Shutdown();
+        }
+    }
+}

Tests/Editor/Transports/UnityTransportTests.cs.meta

@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 1b0137a26ef0140f0bf5167c09eecb96
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Tests/Editor/com.unity.netcode.editortests.asmdef

@@ -9,7 +9,8 @@
         "Unity.Multiplayer.MetricTypes",
         "Unity.Multiplayer.NetStats",
         "Unity.Multiplayer.Tools.MetricTypes",
-        "Unity.Multiplayer.Tools.NetStats"
+        "Unity.Multiplayer.Tools.NetStats",
+        "Unity.Networking.Transport"
     ],
     "optionalUnityReferences": [
         "TestAssemblies"

Tests/Runtime/ClientOnlyConnectionTests.cs

@@ -0,0 +1,78 @@
+using System.Collections;
+using NUnit.Framework;
+using UnityEngine;
+using UnityEngine.TestTools;
+using Unity.Netcode.TestHelpers.Runtime;
+#if UNITY_UNET_PRESENT
+using Unity.Netcode.Transports.UNET;
+#else
+using Unity.Netcode.Transports.UTP;
+#endif
+
+namespace Unity.Netcode.RuntimeTests
+{
+    public class ClientOnlyConnectionTests
+    {
+        private NetworkManager m_ClientNetworkManager;
+        private GameObject m_NetworkManagerGameObject;
+        private WaitForSeconds m_DefaultWaitForTick = new WaitForSeconds(1.0f / 30);
+        private bool m_WasDisconnected;
+        private TimeoutHelper m_TimeoutHelper;
+
+        [SetUp]
+        public void Setup()
+        {
+            m_WasDisconnected = false;
+            m_NetworkManagerGameObject = new GameObject();
+            m_ClientNetworkManager = m_NetworkManagerGameObject.AddComponent<NetworkManager>();
+            m_ClientNetworkManager.NetworkConfig = new NetworkConfig();
+#if UNITY_UNET_PRESENT
+            m_TimeoutHelper = new TimeoutHelper(30);
+            m_ClientNetworkManager.NetworkConfig.NetworkTransport = m_NetworkManagerGameObject.AddComponent<UNetTransport>();
+#else
+            // Default is 1000ms per connection attempt and 60 connection attempts (60s)
+            // Currently there is no easy way to set these values other than in-editor
+            m_TimeoutHelper = new TimeoutHelper(70);
+            m_ClientNetworkManager.NetworkConfig.NetworkTransport = m_NetworkManagerGameObject.AddComponent<UnityTransport>();
+#endif
+        }
+
+        [UnityTest]
+        public IEnumerator ClientFailsToConnect()
+        {
+            // Wait for the disconnected event
+            m_ClientNetworkManager.OnClientDisconnectCallback += ClientNetworkManager_OnClientDisconnectCallback;
+
+            // Only start the client (so it will timeout)
+            m_ClientNetworkManager.StartClient();
+
+#if !UNITY_UNET_PRESENT
+            // Unity Transport throws an error when it times out
+            LogAssert.Expect(LogType.Error, "Failed to connect to server.");
+#endif
+            yield return NetcodeIntegrationTest.WaitForConditionOrTimeOut(() => m_WasDisconnected, m_TimeoutHelper);
+            Assert.False(m_TimeoutHelper.TimedOut, "Timed out waiting for client to timeout waiting to connect!");
+
+            // Shutdown the client
+            m_ClientNetworkManager.Shutdown();
+
+            // Wait for a tick
+            yield return m_DefaultWaitForTick;
+        }
+
+        private void ClientNetworkManager_OnClientDisconnectCallback(ulong clientId)
+        {
+            m_WasDisconnected = true;
+        }
+
+        [TearDown]
+        public void TearDown()
+        {
+            if (m_NetworkManagerGameObject != null)
+            {
+                Object.DestroyImmediate(m_NetworkManagerGameObject);
+            }
+        }
+    }
+}
+

Tests/Runtime/ClientOnlyConnectionTests.cs.meta

@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 639fe2161ab25c54f94ce6eb991e668a
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Tests/Runtime/Components/NetworkVariableTestComponent.cs

@@ -103,46 +103,6 @@ namespace Unity.Netcode.RuntimeTests
             m_NetworkVariableUInt = new NetworkVariable<uint>(1);
             m_NetworkVariableUShort = new NetworkVariable<ushort>(1);
 
-            m_NetworkVariableBool = new NetworkVariable<bool>(NetworkVariableReadPermission.Everyone);
-            m_NetworkVariableByte = new NetworkVariable<byte>(NetworkVariableReadPermission.Everyone);
-            m_NetworkVariableColor = new NetworkVariable<Color>(NetworkVariableReadPermission.Everyone);
-            m_NetworkVariableColor32 = new NetworkVariable<Color32>(NetworkVariableReadPermission.Everyone);
-            m_NetworkVariableDouble = new NetworkVariable<double>(NetworkVariableReadPermission.Everyone);
-            m_NetworkVariableFloat = new NetworkVariable<float>(NetworkVariableReadPermission.Everyone);
-            m_NetworkVariableInt = new NetworkVariable<int>(NetworkVariableReadPermission.Everyone);
-            m_NetworkVariableLong = new NetworkVariable<long>(NetworkVariableReadPermission.Everyone);
-            m_NetworkVariableSByte = new NetworkVariable<sbyte>(NetworkVariableReadPermission.Everyone);
-            m_NetworkVariableQuaternion = new NetworkVariable<Quaternion>(NetworkVariableReadPermission.Everyone);
-            m_NetworkVariableShort = new NetworkVariable<short>(NetworkVariableReadPermission.Everyone);
-            m_NetworkVariableVector4 = new NetworkVariable<Vector4>(NetworkVariableReadPermission.Everyone);
-            m_NetworkVariableVector3 = new NetworkVariable<Vector3>(NetworkVariableReadPermission.Everyone);
-            m_NetworkVariableVector2 = new NetworkVariable<Vector2>(NetworkVariableReadPermission.Everyone);
-            m_NetworkVariableRay = new NetworkVariable<Ray>(NetworkVariableReadPermission.Everyone);
-            m_NetworkVariableULong = new NetworkVariable<ulong>(NetworkVariableReadPermission.Everyone);
-            m_NetworkVariableUInt = new NetworkVariable<uint>(NetworkVariableReadPermission.Everyone);
-            m_NetworkVariableUShort = new NetworkVariable<ushort>(NetworkVariableReadPermission.Everyone);
-
-
-            // NetworkVariable Value Type and NetworkVariableSettings Constructor Test Coverage
-            m_NetworkVariableBool = new NetworkVariable<bool>(NetworkVariableReadPermission.Everyone, true);
-            m_NetworkVariableByte = new NetworkVariable<byte>(NetworkVariableReadPermission.Everyone, 0);
-            m_NetworkVariableColor = new NetworkVariable<Color>(NetworkVariableReadPermission.Everyone, new Color(1, 1, 1, 1));
-            m_NetworkVariableColor32 = new NetworkVariable<Color32>(NetworkVariableReadPermission.Everyone, new Color32(1, 1, 1, 1));
-            m_NetworkVariableDouble = new NetworkVariable<double>(NetworkVariableReadPermission.Everyone, 1.0);
-            m_NetworkVariableFloat = new NetworkVariable<float>(NetworkVariableReadPermission.Everyone, 1.0f);
-            m_NetworkVariableInt = new NetworkVariable<int>(NetworkVariableReadPermission.Everyone, 1);
-            m_NetworkVariableLong = new NetworkVariable<long>(NetworkVariableReadPermission.Everyone, 1);
-            m_NetworkVariableSByte = new NetworkVariable<sbyte>(NetworkVariableReadPermission.Everyone, 0);
-            m_NetworkVariableQuaternion = new NetworkVariable<Quaternion>(NetworkVariableReadPermission.Everyone, Quaternion.identity);
-            m_NetworkVariableShort = new NetworkVariable<short>(NetworkVariableReadPermission.Everyone, 1);
-            m_NetworkVariableVector4 = new NetworkVariable<Vector4>(NetworkVariableReadPermission.Everyone, new Vector4(1, 1, 1, 1));
-            m_NetworkVariableVector3 = new NetworkVariable<Vector3>(NetworkVariableReadPermission.Everyone, new Vector3(1, 1, 1));
-            m_NetworkVariableVector2 = new NetworkVariable<Vector2>(NetworkVariableReadPermission.Everyone, new Vector2(1, 1));
-            m_NetworkVariableRay = new NetworkVariable<Ray>(NetworkVariableReadPermission.Everyone, new Ray());
-            m_NetworkVariableULong = new NetworkVariable<ulong>(NetworkVariableReadPermission.Everyone, 1);
-            m_NetworkVariableUInt = new NetworkVariable<uint>(NetworkVariableReadPermission.Everyone, 1);
-            m_NetworkVariableUShort = new NetworkVariable<ushort>(NetworkVariableReadPermission.Everyone, 1);
-
             // Use this nifty class: NetworkVariableHelper
             // Tracks if NetworkVariable changed invokes the OnValueChanged callback for the given instance type
             Bool_Var = new NetworkVariableHelper<bool>(m_NetworkVariableBool);
@@ -193,7 +153,7 @@ namespace Unity.Netcode.RuntimeTests
         {
             if (EnableTesting)
             {
-                //Added timeout functionality for near future changes to NetworkVariables and the Snapshot system
+                //Added timeout functionality for near future changes to NetworkVariables
                 if (!m_FinishedTests && m_ChangesAppliedToNetworkVariables)
                 {
                     //We finish testing if all NetworkVariables changed their value or we timed out waiting for

Tests/Runtime/Metrics/ConnectionMetricsTests.cs

@@ -0,0 +1,69 @@
+#if MULTIPLAYER_TOOLS
+#if MULTIPLAYER_TOOLS_1_0_0_PRE_7
+
+using System.Collections;
+using System.Collections.Generic;
+using NUnit.Framework;
+using Unity.Multiplayer.Tools.MetricTypes;
+using Unity.Netcode.TestHelpers.Runtime;
+using Unity.Netcode.TestHelpers.Runtime.Metrics;
+using UnityEngine.TestTools;
+
+namespace Unity.Netcode.RuntimeTests.Metrics
+{
+    [TestFixture(ClientCount.OneClient, HostOrServer.Host)]
+    [TestFixture(ClientCount.TwoClients, HostOrServer.Host)]
+    [TestFixture(ClientCount.OneClient, HostOrServer.Server)]
+    [TestFixture(ClientCount.TwoClients, HostOrServer.Server)]
+    public class ConnectionMetricsTests : NetcodeIntegrationTest
+    {
+        protected override int NumberOfClients => m_ClientCount;
+
+        private int m_ClientCount;
+
+        public enum ClientCount
+        {
+            OneClient = 1,
+            TwoClients,
+        }
+
+        public ConnectionMetricsTests(ClientCount clientCount, HostOrServer hostOrServer)
+            : base(hostOrServer)
+        {
+            m_ClientCount = (int)clientCount;
+        }
+
+        private int GetClientCountForFixture()
+        {
+            return m_ClientCount + ((m_UseHost) ? 1 : 0);
+        }
+
+        [UnityTest]
+        public IEnumerator UpdateConnectionCountOnServer()
+        {
+            var waitForGaugeValues = new WaitForGaugeMetricValues((m_ServerNetworkManager.NetworkMetrics as NetworkMetrics).Dispatcher, NetworkMetricTypes.ConnectedClients);
+
+            yield return waitForGaugeValues.WaitForMetricsReceived();
+
+            var value = waitForGaugeValues.AssertMetricValueHaveBeenFound();
+            Assert.AreEqual(GetClientCountForFixture(), value);
+        }
+
+        [UnityTest]
+        public IEnumerator UpdateConnectionCountOnClient()
+        {
+            foreach (var clientNetworkManager in m_ClientNetworkManagers)
+            {
+                var waitForGaugeValues = new WaitForGaugeMetricValues((clientNetworkManager.NetworkMetrics as NetworkMetrics).Dispatcher, NetworkMetricTypes.ConnectedClients);
+
+                yield return waitForGaugeValues.WaitForMetricsReceived();
+
+                var value = waitForGaugeValues.AssertMetricValueHaveBeenFound();
+                Assert.AreEqual(1, value);
+            }
+        }
+    }
+}
+
+#endif
+#endif

Tests/Runtime/Metrics/ConnectionMetricsTests.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: 1845aef61dbb4f2b9d2be9145262ab90
+timeCreated: 1647023529

Tests/Runtime/Metrics/MessagingMetricsTests.cs

@@ -39,7 +39,7 @@ namespace Unity.Netcode.RuntimeTests.Metrics
 
             var networkMessageSentMetricValues = waitForMetricValues.AssertMetricValuesHaveBeenFound();
 
-            // We should have 1 NamedMessage and some potential SnapshotMessage
+            // We should have 1 NamedMessage
             Assert.That(networkMessageSentMetricValues, Has.Exactly(1).Matches<NetworkMessageEvent>(x => x.Name == nameof(NamedMessage)));
         }
 
@@ -85,7 +85,7 @@ namespace Unity.Netcode.RuntimeTests.Metrics
             yield return waitForMetricValues.WaitForMetricsReceived();
 
             var networkMessageReceivedValues = waitForMetricValues.AssertMetricValuesHaveBeenFound();
-            // We should have 1 NamedMessage and some potential SnapshotMessage
+            // We should have 1 NamedMessage
             Assert.That(networkMessageReceivedValues, Has.Exactly(1).Matches<NetworkMessageEvent>(x => x.Name == nameof(NamedMessage)));
         }
 

Tests/Runtime/Metrics/NetworkObjectMetricsTests.cs

@@ -189,6 +189,76 @@ namespace Unity.Netcode.RuntimeTests.Metrics
             Assert.AreEqual(1, objectDestroyedSentMetricValues.Select(x => x.BytesCount).Distinct().Count());
             Assert.That(objectDestroyedSentMetricValues.Select(x => x.BytesCount), Has.All.Not.EqualTo(0));
         }
+
+#if MULTIPLAYER_TOOLS_1_0_0_PRE_7
+        [UnityTest]
+        public IEnumerator TrackNetworkObjectCountAfterSpawnOnServer()
+        {
+            SpawnNetworkObject();
+
+            var waitForGaugeValues = new WaitForGaugeMetricValues(ServerMetrics.Dispatcher, NetworkMetricTypes.NetworkObjects);
+
+            yield return s_DefaultWaitForTick;
+            yield return waitForGaugeValues.WaitForMetricsReceived();
+
+            var value = waitForGaugeValues.AssertMetricValueHaveBeenFound();
+            Assert.AreEqual(3, value);
+        }
+
+        [UnityTest]
+        public IEnumerator TrackNetworkObjectCountAfterSpawnOnClient()
+        {
+            SpawnNetworkObject();
+
+            //By default, we have 2 network objects
+            //There's a slight delay between the spawn on the server and the spawn on the client
+            //We want to have metrics when the value is different than the 2 default one to confirm the client has the new value
+            var waitForGaugeValues = new WaitForGaugeMetricValues(ClientMetrics.Dispatcher, NetworkMetricTypes.NetworkObjects, metric => (int)metric != 2);
+
+            yield return waitForGaugeValues.WaitForMetricsReceived();
+
+            var value = waitForGaugeValues.AssertMetricValueHaveBeenFound();
+            Assert.AreEqual(3, value);
+        }
+
+        [UnityTest]
+        public IEnumerator TrackNetworkObjectCountAfterDespawnOnServer()
+        {
+            var objectList = Server.SpawnManager.SpawnedObjectsList;
+            for (int i = objectList.Count - 1; i >= 0; --i)
+            {
+                objectList.ElementAt(i).Despawn();
+            }
+
+            var waitForGaugeValues = new WaitForGaugeMetricValues(ServerMetrics.Dispatcher, NetworkMetricTypes.NetworkObjects);
+
+            yield return s_DefaultWaitForTick;
+            yield return waitForGaugeValues.WaitForMetricsReceived();
+
+            var value = waitForGaugeValues.AssertMetricValueHaveBeenFound();
+            Assert.AreEqual(0, value);
+        }
+
+        [UnityTest]
+        public IEnumerator TrackNetworkObjectCountAfterDespawnOnClient()
+        {
+            var objectList = Server.SpawnManager.SpawnedObjectsList;
+            for (int i = objectList.Count - 1; i >= 0; --i)
+            {
+                objectList.ElementAt(i).Despawn();
+            }
+
+            //By default, we have 2 network objects
+            //There's a slight delay between the spawn on the server and the spawn on the client
+            //We want to have metrics when the value is different than the 2 default one to confirm the client has the new value
+            var waitForGaugeValues = new WaitForGaugeMetricValues(ClientMetrics.Dispatcher, NetworkMetricTypes.NetworkObjects, metric => (int)metric != 2);
+
+            yield return waitForGaugeValues.WaitForMetricsReceived();
+
+            var value = waitForGaugeValues.AssertMetricValueHaveBeenFound();
+            Assert.AreEqual(0, value);
+        }
+#endif
     }
 }
 #endif

Tests/Runtime/Metrics/PacketLossMetricsTests.cs

@@ -0,0 +1,89 @@
+#if MULTIPLAYER_TOOLS
+#if MULTIPLAYER_TOOLS_1_0_0_PRE_7
+
+using System;
+using System.Collections;
+using NUnit.Framework;
+using Unity.Collections;
+using Unity.Multiplayer.Tools.MetricTypes;
+using Unity.Netcode.TestHelpers.Runtime;
+using Unity.Netcode.TestHelpers.Runtime.Metrics;
+using Unity.Netcode.Transports.UTP;
+using UnityEngine;
+using UnityEngine.TestTools;
+
+namespace Unity.Netcode.RuntimeTests.Metrics
+{
+    public class PacketLossMetricsTests : NetcodeIntegrationTest
+    {
+        protected override int NumberOfClients => 1;
+        private readonly int m_PacketLossRate = 25;
+        private int m_DropInterval = 5;
+
+        public PacketLossMetricsTests()
+            : base(HostOrServer.Server)
+        {}
+
+        protected override void OnOneTimeSetup()
+        {
+            m_NetworkTransport = NetcodeIntegrationTestHelpers.InstanceTransport.UTP;
+        }
+
+        protected override void OnServerAndClientsCreated()
+        {
+            var clientTransport = (UnityTransport)m_ClientNetworkManagers[0].NetworkConfig.NetworkTransport;
+            clientTransport.SetDebugSimulatorParameters(0, 0, m_PacketLossRate);
+
+            base.OnServerAndClientsCreated();
+        }
+
+        [UnityTest]
+        public IEnumerator TrackPacketLossAsServer()
+        {
+            var waitForPacketLossMetric = new WaitForGaugeMetricValues((m_ServerNetworkManager.NetworkMetrics as NetworkMetrics).Dispatcher,
+                NetworkMetricTypes.PacketLoss,
+                metric => metric == 0.0d);
+
+            for (int i = 0; i < 1000; ++i)
+            {
+                using (var writer = new FastBufferWriter(sizeof(byte), Allocator.Persistent))
+                {
+                    writer.WriteByteSafe(42);
+                    m_ServerNetworkManager.CustomMessagingManager.SendNamedMessage("Test", m_ServerNetworkManager.ConnectedClientsIds, writer);
+                }
+            }
+
+            yield return waitForPacketLossMetric.WaitForMetricsReceived();
+
+            var packetLossValue = waitForPacketLossMetric.AssertMetricValueHaveBeenFound();
+            Assert.AreEqual(0d, packetLossValue);
+        }
+
+        [UnityTest]
+        public IEnumerator TrackPacketLossAsClient()
+        {
+            double packetLossRate = m_PacketLossRate/100d;
+            var clientNetworkManager = m_ClientNetworkManagers[0];
+            var waitForPacketLossMetric = new WaitForGaugeMetricValues((clientNetworkManager.NetworkMetrics as NetworkMetrics).Dispatcher,
+                NetworkMetricTypes.PacketLoss,
+                metric => Math.Abs(metric - packetLossRate) < Double.Epsilon);
+
+            for (int i = 0; i < 1000; ++i)
+            {
+                using (var writer = new FastBufferWriter(sizeof(byte), Allocator.Persistent))
+                {
+                    writer.WriteByteSafe(42);
+                    m_ServerNetworkManager.CustomMessagingManager.SendNamedMessage("Test", m_ServerNetworkManager.ConnectedClientsIds, writer);
+                }
+            }
+
+            yield return waitForPacketLossMetric.WaitForMetricsReceived();
+
+            var packetLossValue = waitForPacketLossMetric.AssertMetricValueHaveBeenFound();
+            Assert.AreEqual(packetLossRate, packetLossValue);
+        }
+    }
+}
+
+#endif
+#endif

Tests/Runtime/Metrics/PacketLossMetricsTests.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: 12e64da4670d49a4a89da38d18e64396
+timeCreated: 1648133968

Tests/Runtime/Metrics/PacketMetricsTests.cs

@@ -1,5 +1,5 @@
 #if MULTIPLAYER_TOOLS
-#if MULTIPLAYER_TOOLS_1_0_0_PRE_4
+#if MULTIPLAYER_TOOLS_1_0_0_PRE_7
 using System.Collections;
 using NUnit.Framework;
 using Unity.Collections;
@@ -15,11 +15,7 @@ namespace Unity.Netcode.RuntimeTests.Metrics
 
         protected override void OnOneTimeSetup()
         {
-#if UTP_ADAPTER
             m_NetworkTransport = NetcodeIntegrationTestHelpers.InstanceTransport.UTP;
-#else
-            m_NetworkTransport = NetcodeIntegrationTestHelpers.InstanceTransport.SIP;
-#endif
             base.OnOneTimeSetup();
         }
 

Tests/Runtime/Metrics/RttMetricsTests.cs

@@ -1,5 +1,5 @@
 #if MULTIPLAYER_TOOLS
-#if MULTIPLAYER_TOOLS_1_0_0_PRE_4
+#if MULTIPLAYER_TOOLS_1_0_0_PRE_7
 
 using System.Collections;
 using System.Collections.Generic;
@@ -46,11 +46,7 @@ namespace Unity.Netcode.RuntimeTests.Metrics
         /// </summary>
         protected override void OnOneTimeSetup()
         {
-#if UTP_ADAPTER
             m_NetworkTransport = NetcodeIntegrationTestHelpers.InstanceTransport.UTP;
-#else
-            m_NetworkTransport = NetcodeIntegrationTestHelpers.InstanceTransport.SIP;
-#endif
         }
 
         [UnityTest]
@@ -92,7 +88,7 @@ namespace Unity.Netcode.RuntimeTests.Metrics
             foreach (var clientGaugeMetricValue in clientGaugeMetricValues)
             {
                 var rttValue = clientGaugeMetricValue.AssertMetricValueHaveBeenFound();
-                Assert.That(rttValue, Is.GreaterThanOrEqualTo(1f));
+                Assert.That(rttValue, Is.GreaterThanOrEqualTo(1e-3f));
             }
         }
     }

Tests/Runtime/NetworkAnimator/NetworkAnimatorTests.cs

@@ -1,3 +1,4 @@
+#if COM_UNITY_MODULES_ANIMATION
 using System.Collections;
 using System.Collections.Generic;
 using NUnit.Framework;
@@ -235,3 +236,4 @@ namespace Unity.Netcode.RuntimeTests
         }
     }
 }
+#endif // COM_UNITY_MODULES_ANIMATION

Tests/Runtime/NetworkManagerTransportTests.cs

@@ -0,0 +1,133 @@
+using System;
+using System.Collections;
+using UnityEngine;
+using UnityEngine.TestTools;
+using NUnit.Framework;
+using Unity.Netcode.TestHelpers.Runtime;
+using Object = UnityEngine.Object;
+
+namespace Unity.Netcode.RuntimeTests
+{
+    [TestFixture(HostOrServer.Host)]
+    [TestFixture(HostOrServer.Server)]
+    public class NetworkManagerTransportTests : NetcodeIntegrationTest
+    {
+        protected override int NumberOfClients => 1;
+
+        private bool m_CanStartServerAndClients = false;
+
+        public NetworkManagerTransportTests(HostOrServer hostOrServer) : base(hostOrServer) { }
+
+        protected override IEnumerator OnSetup()
+        {
+            m_CanStartServerAndClients = false;
+            return base.OnSetup();
+        }
+
+        protected override bool CanStartServerAndClients()
+        {
+            return m_CanStartServerAndClients;
+        }
+
+        /// <summary>
+        /// Validate that if the NetworkTransport fails to start the NetworkManager
+        /// will not continue the startup process and will shut itself down.
+        /// </summary>
+        /// <param name="testClient">if true it will test the client side</param>
+        [UnityTest]
+        public IEnumerator DoesNotStartWhenTransportFails([Values] bool testClient)
+        {
+            // The error message we should expect
+            var messageToCheck = "";
+            if (!testClient)
+            {
+                Object.DestroyImmediate(m_ServerNetworkManager.NetworkConfig.NetworkTransport);
+                m_ServerNetworkManager.NetworkConfig.NetworkTransport = m_ServerNetworkManager.gameObject.AddComponent<FailedTransport>();
+                m_ServerNetworkManager.NetworkConfig.NetworkTransport.Initialize(m_ServerNetworkManager);
+                // The error message we should expect
+                messageToCheck = $"Server is shutting down due to network transport start failure of {m_ServerNetworkManager.NetworkConfig.NetworkTransport.GetType().Name}!";
+            }
+            else
+            {
+                foreach (var client in m_ClientNetworkManagers)
+                {
+                    Object.DestroyImmediate(client.NetworkConfig.NetworkTransport);
+                    client.NetworkConfig.NetworkTransport = client.gameObject.AddComponent<FailedTransport>();
+                    client.NetworkConfig.NetworkTransport.Initialize(m_ServerNetworkManager);
+                }
+                // The error message we should expect
+                messageToCheck = $"Client is shutting down due to network transport start failure of {m_ClientNetworkManagers[0].NetworkConfig.NetworkTransport.GetType().Name}!";
+            }
+
+            // Trap for the nested NetworkManager exception
+            LogAssert.Expect(LogType.Error, messageToCheck);
+            m_CanStartServerAndClients = true;
+            // Due to other errors, we must not send clients if testing the server-host side
+            // We can test both server and client(s) when testing client-side only
+            if (testClient)
+            {
+                NetcodeIntegrationTestHelpers.Start(m_UseHost, m_ServerNetworkManager, m_ClientNetworkManagers);
+                yield return s_DefaultWaitForTick;
+                foreach (var client in m_ClientNetworkManagers)
+                {
+                    Assert.False(client.IsListening);
+                    Assert.False(client.IsConnectedClient);
+                }
+            }
+            else
+            {
+                NetcodeIntegrationTestHelpers.Start(m_UseHost, m_ServerNetworkManager, new NetworkManager[] { });
+                yield return s_DefaultWaitForTick;
+                Assert.False(m_ServerNetworkManager.IsListening);
+            }
+        }
+    }
+
+    /// <summary>
+    /// Does nothing but simulate a transport that failed to start
+    /// </summary>
+    public class FailedTransport : TestingNetworkTransport
+    {
+        public override void Shutdown()
+        {
+        }
+
+        public override ulong ServerClientId => 0;
+
+        public override NetworkEvent PollEvent(out ulong clientId, out ArraySegment<byte> payload, out float receiveTime)
+        {
+            clientId = 0;
+            payload = new ArraySegment<byte>();
+            receiveTime = 0;
+            return NetworkEvent.Nothing;
+        }
+        public override bool StartClient()
+        {
+            // Simulate failure, always return false
+            return false;
+        }
+        public override bool StartServer()
+        {
+            // Simulate failure, always return false
+            return false;
+        }
+        public override void Send(ulong clientId, ArraySegment<byte> payload, NetworkDelivery networkDelivery)
+        {
+        }
+
+        public override void DisconnectRemoteClient(ulong clientId)
+        {
+        }
+
+        public override void Initialize(NetworkManager networkManager = null)
+        {
+        }
+        public override ulong GetCurrentRtt(ulong clientId)
+        {
+            return 0;
+        }
+        public override void DisconnectLocalClient()
+        {
+        }
+    }
+}

Tests/Runtime/NetworkManagerTransportTests.cs.meta

@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 798d76599e527b245a14b7cc9cfd2607
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Tests/Runtime/NetworkObject/NetworkObjectDontDestroyWithOwnerTests.cs

@@ -1,78 +1,55 @@
 using System.Collections;
-using System.Collections.Generic;
+using System.Linq;
 using NUnit.Framework;
 using UnityEngine;
 using UnityEngine.TestTools;
 using Unity.Netcode.TestHelpers.Runtime;
-using Object = UnityEngine.Object;
+
 
 namespace Unity.Netcode.RuntimeTests
 {
-    public class NetworkObjectDontDestroyWithOwnerTests
+    [TestFixture(HostOrServer.Host)]
+    [TestFixture(HostOrServer.Server)]
+    public class NetworkObjectDontDestroyWithOwnerTests : NetcodeIntegrationTest
     {
+        private const int k_NumberObjectsToSpawn = 32;
+        protected override int NumberOfClients => 1;
+
+        protected GameObject m_PrefabToSpawn;
+
+        public NetworkObjectDontDestroyWithOwnerTests(HostOrServer hostOrServer) : base(hostOrServer) { }
+
+        protected override void OnServerAndClientsCreated()
+        {
+            m_PrefabToSpawn = CreateNetworkObjectPrefab("ClientOwnedObject");
+            m_PrefabToSpawn.GetComponent<NetworkObject>().DontDestroyWithOwner = true;
+        }
+
         [UnityTest]
         public IEnumerator DontDestroyWithOwnerTest()
         {
-            // create server and client instances
-            NetcodeIntegrationTestHelpers.Create(1, out NetworkManager server, out NetworkManager[] clients);
+            var client = m_ClientNetworkManagers[0];
+            var clientId = client.LocalClientId;
+            var networkObjects = SpawnObjects(m_PrefabToSpawn, m_ClientNetworkManagers[0], k_NumberObjectsToSpawn);
 
-            // create prefab
-            var gameObject = new GameObject("ClientOwnedObject");
-            var networkObject = gameObject.AddComponent<NetworkObject>();
-            networkObject.DontDestroyWithOwner = true;
-            NetcodeIntegrationTestHelpers.MakeNetworkObjectTestPrefab(networkObject);
-
-            server.NetworkConfig.NetworkPrefabs.Add(new NetworkPrefab()
-            {
-                Prefab = gameObject
-            });
-
-            for (int i = 0; i < clients.Length; i++)
-            {
-                clients[i].NetworkConfig.NetworkPrefabs.Add(new NetworkPrefab()
-                {
-                    Prefab = gameObject
-                });
-            }
-
-            // start server and connect clients
-            NetcodeIntegrationTestHelpers.Start(false, server, clients);
-
-            // wait for connection on client side
-            yield return NetcodeIntegrationTestHelpers.WaitForClientsConnected(clients);
-
-            // wait for connection on server side
-            yield return NetcodeIntegrationTestHelpers.WaitForClientConnectedToServer(server);
-
-            // network objects
-            var networkObjects = new List<NetworkObject>();
-
-            // create instances
-            for (int i = 0; i < 32; i++)
-            {
-                var no = Object.Instantiate(gameObject).GetComponent<NetworkObject>();
-                no.NetworkManagerOwner = server;
-                networkObjects.Add(no);
-                no.SpawnWithOwnership(clients[0].LocalClientId);
-            }
-
-            // wait for object spawn on client
-            yield return NetcodeIntegrationTest.WaitForConditionOrTimeOut(() => clients[0].SpawnManager.SpawnedObjects.Count == 32);
+            // wait for object spawn on client to reach k_NumberObjectsToSpawn + 1 (k_NumberObjectsToSpawn and 1 for the player)
+            yield return WaitForConditionOrTimeOut(() => client.SpawnManager.GetClientOwnedObjects(clientId).Count() == k_NumberObjectsToSpawn + 1);
+            Assert.False(s_GlobalTimeoutHelper.TimedOut, $"Timed out waiting for client to have 33 NetworkObjects spawned! Only {client.SpawnManager.GetClientOwnedObjects(clientId).Count()} were assigned!");
 
             // disconnect the client that owns all the clients
-            NetcodeIntegrationTestHelpers.StopOneClient(clients[0]);
+            NetcodeIntegrationTestHelpers.StopOneClient(client);
 
+            var remainingClients = Mathf.Max(0, TotalClients - 1);
             // wait for disconnect
-            yield return NetcodeIntegrationTest.WaitForConditionOrTimeOut(() => server.ConnectedClients.Count == 0);
+            yield return WaitForConditionOrTimeOut(() => m_ServerNetworkManager.ConnectedClients.Count == remainingClients);
+            Assert.False(s_GlobalTimeoutHelper.TimedOut, "Timed out waiting for client to disconnect!");
 
             for (int i = 0; i < networkObjects.Count; i++)
             {
+                var networkObject = networkObjects[i].GetComponent<NetworkObject>();
                 // ensure ownership was transferred back
-                Assert.That(networkObjects[i].OwnerClientId == server.ServerClientId);
-            }
-
-            // cleanup
-            NetcodeIntegrationTestHelpers.Destroy();
+                Assert.That(networkObject.OwnerClientId == m_ServerNetworkManager.LocalClientId);
+            }
         }
     }
 }

Tests/Runtime/NetworkObject/NetworkObjectNetworkClientOwnedObjectsTests.cs

@@ -42,7 +42,7 @@ namespace Unity.Netcode.RuntimeTests
             yield return s_DefaultWaitForTick;
 
             // The object is owned by server
-            Assert.False(m_ServerNetworkManager.ConnectedClients[m_ClientNetworkManagers[0].LocalClientId].OwnedObjects.Any(x => x.NetworkObjectId == serverObject.NetworkObjectId));
+            Assert.False(m_ServerNetworkManager.SpawnManager.GetClientOwnedObjects(m_ClientNetworkManagers[0].LocalClientId).Any(x => x.NetworkObjectId == serverObject.NetworkObjectId));
 
             // Change the ownership
             serverObject.ChangeOwnership(m_ClientNetworkManagers[0].LocalClientId);
@@ -51,8 +51,8 @@ namespace Unity.Netcode.RuntimeTests
             yield return s_DefaultWaitForTick;
 
             // Ensure it's now added to the list
-            Assert.True(m_ServerNetworkManager.ConnectedClients[m_ClientNetworkManagers[0].LocalClientId].OwnedObjects.Any(x => x.NetworkObjectId == serverObject.NetworkObjectId));
-
+            Assert.True(m_ClientNetworkManagers[0].SpawnManager.GetClientOwnedObjects(m_ClientNetworkManagers[0].LocalClientId).Any(x => x.NetworkObjectId == serverObject.NetworkObjectId));
+            Assert.True(m_ServerNetworkManager.SpawnManager.GetClientOwnedObjects(m_ClientNetworkManagers[0].LocalClientId).Any(x => x.NetworkObjectId == serverObject.NetworkObjectId));
         }
     }
 }