Reduce garbage allocation in SyncVar Deserialize when syncvar has no hook

Assets/Mirror/Core/NetworkBehaviour.cs

@@ -766,6 +766,13 @@ public static bool SyncVarNetworkIdentityEqual(NetworkIdentity newIdentity, uint
             return newNetId == netIdField;
         }
 
+        // Anonymous method instance is instantiated upon entering the method containing it. 
+        // Deferred hooks should only be added in a nested method to avoid allocations when not adding a deferred hook.
+        void AddDeferredSyncVarHook<T>(Action<T, T> hook, T capturedPrevious, T capturedNew)
+        {
+            deferredSyncVarHooks.Add(() => hook(capturedPrevious, capturedNew));
+        }
+
         // move the [SyncVar] generated OnDeserialize C# to avoid much IL.
         //
         // before:
@@ -832,7 +839,7 @@ public void GeneratedSyncVarDeserialize<T>(ref T field, Action<T, T> OnChanged,
                         // Capture values in closure for deferred execution
                         T capturedPrevious = previous;
                         T capturedNew = field;
-                        deferredSyncVarHooks.Add(() => OnChanged(capturedPrevious, capturedNew));
+                        AddDeferredSyncVarHook(OnChanged, capturedPrevious, capturedNew);
                     }
                     else
                     {
@@ -910,7 +917,7 @@ public void GeneratedSyncVarDeserialize_GameObject(ref GameObject field, Action<
                     {
                         GameObject capturedPrevious = previousGameObject;
                         GameObject capturedNew = field;
-                        deferredSyncVarHooks.Add(() => OnChanged(capturedPrevious, capturedNew));
+                        AddDeferredSyncVarHook(OnChanged, capturedPrevious, capturedNew);
                     }
                     else
                     {
@@ -988,7 +995,7 @@ public void GeneratedSyncVarDeserialize_NetworkIdentity(ref NetworkIdentity fiel
                     {
                         NetworkIdentity capturedPrevious = previousIdentity;
                         NetworkIdentity capturedNew = field;
-                        deferredSyncVarHooks.Add(() => OnChanged(capturedPrevious, capturedNew));
+                        AddDeferredSyncVarHook(OnChanged, capturedPrevious, capturedNew);
                     }
                     else
                     {
@@ -1068,7 +1075,7 @@ public void GeneratedSyncVarDeserialize_NetworkBehaviour<T>(ref T field, Action<
                     {
                         T capturedPrevious = previousBehaviour;
                         T capturedNew = field;
-                        deferredSyncVarHooks.Add(() => OnChanged(capturedPrevious, capturedNew));
+                        AddDeferredSyncVarHook(OnChanged, capturedPrevious, capturedNew);
                     }
                     else
                     {

Assets/Mirror/Core/SyncDictionary.cs

@@ -378,9 +378,7 @@ void AddOperation(Operation op, TKey key, TValue item, TValue oldItem, bool chec
                     TKey capturedKey = key;
                     TValue capturedItem = item;
                     TValue capturedOld = oldItem;
-
-                    networkBehaviour.deferredSyncCollectionActions.Add(() =>
-                        InvokeActions(capturedOp, capturedKey, capturedItem, capturedOld));
+                    AddDeferredOperation(capturedOp, capturedKey, capturedItem, capturedOld);
                 }
                 else
                 {
@@ -390,6 +388,12 @@ void AddOperation(Operation op, TKey key, TValue item, TValue oldItem, bool chec
             }
         }
 
+        void AddDeferredOperation(Operation capturedOp, TKey capturedKey, TValue capturedItem, TValue capturedOld)
+        {
+            networkBehaviour.deferredSyncCollectionActions.Add(() =>
+                InvokeActions(capturedOp, capturedKey, capturedItem, capturedOld));
+        }
+
         void InvokeActions(Operation op, TKey key, TValue item, TValue oldItem)
         {
             switch (op)

Assets/Mirror/Core/SyncList.cs

@@ -139,9 +139,7 @@ void AddOperation(Operation op, int itemIndex, T oldItem, T newItem, bool checkA
                     int capturedIndex = itemIndex;
                     T capturedOld = oldItem;
                     T capturedNew = newItem;
-
-                    networkBehaviour.deferredSyncCollectionActions.Add(() =>
-                        InvokeActions(capturedOp, capturedIndex, capturedOld, capturedNew));
+                    AddDeferredOperation(capturedOp, capturedIndex, capturedOld, capturedNew);
                 }
                 else
                 {
@@ -151,6 +149,12 @@ void AddOperation(Operation op, int itemIndex, T oldItem, T newItem, bool checkA
             }
         }
 
+        void AddDeferredOperation(Operation capturedOp, int capturedIndex, T capturedOld, T capturedNew)
+        {
+            networkBehaviour.deferredSyncCollectionActions.Add(() =>
+                InvokeActions(capturedOp, capturedIndex, capturedOld, capturedNew));
+        }
+
         void InvokeActions(Operation op, int itemIndex, T oldItem, T newItem)
         {
             switch (op)

Assets/Mirror/Core/SyncSet.cs

@@ -130,9 +130,7 @@ void AddOperation(Operation op, T oldItem, T newItem, bool checkAccess, bool sho
                     Operation capturedOp = op;
                     T capturedOld = oldItem;
                     T capturedNew = newItem;
-
-                    networkBehaviour.deferredSyncCollectionActions.Add(() =>
-                        InvokeActions(capturedOp, capturedOld, capturedNew));
+                    AddDeferredOperation(capturedOp, capturedOld, capturedNew);
                 }
                 else
                 {
@@ -142,6 +140,12 @@ void AddOperation(Operation op, T oldItem, T newItem, bool checkAccess, bool sho
             }
         }
 
+        void AddDeferredOperation(Operation capturedOp, T capturedOld, T capturedNew)
+        {
+            networkBehaviour.deferredSyncCollectionActions.Add(() =>
+                InvokeActions(capturedOp, capturedOld, capturedNew));
+        }
+
         void AddOperation(Operation op, bool checkAccess) => AddOperation(op, default, default, checkAccess, true);
 
         void InvokeActions(Operation op, T oldItem, T newItem)