refactor!: remove SnapshotSystem (#1852)

Author: 0xFA11

com.unity.netcode.gameobjects/CHANGELOG.md

@@ -19,6 +19,7 @@ Additional documentation and release notes are available at [Multiplayer Documen
 
 ### Removed
 
+- Removed `SnapshotSystem` (#1852)
 - Removed `com.unity.modules.animation`, `com.unity.modules.physics` and `com.unity.modules.physics2d` dependencies from the package (#1812)
 
 ### Fixed

com.unity.netcode.gameobjects/Components/NetworkTransform.cs

@@ -691,7 +691,6 @@ private void OnNetworkStateChanged(NetworkTransformState oldState, NetworkTransf
         {
             if (!NetworkObject.IsSpawned)
             {
-                // todo MTT-849 should never happen but yet it does! maybe revisit/dig after NetVar updates and snapshot system lands?
                 return;
             }
 

com.unity.netcode.gameobjects/Runtime/Configuration/NetworkConfig.cs

@@ -138,19 +138,6 @@ public class NetworkConfig
         /// </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>