refactor: Splitting MessagingSystem.SendMessage into a second part … (#1642)

* Splitting MessagingSystem.SendMessage into a second part, SendPreSerializedMessage. This allows SnapshotSystem to send larger messages, while saving an allocation and a copy.

* refactor: Splitting MessagingSystem.SendMessage into second part, SendPreSerializedMessage. This allows SnapshotSystem to send larger messages, while saving an allocation and a copy.

Author: jeffreyrainy

com.unity.netcode.gameobjects/Runtime/Core/NetworkManager.cs

@@ -1506,6 +1506,12 @@ internal int SendMessage<T>(ref T message, NetworkDelivery delivery, ulong clien
             return MessagingSystem.SendMessage(ref message, delivery, clientId);
         }
 
+        internal int SendPreSerializedMessage<T>(in FastBufferWriter writer, int maxSize, ref T message, NetworkDelivery delivery, ulong clientId)
+            where T : INetworkMessage
+        {
+            return MessagingSystem.SendPreSerializedMessage(writer, maxSize, ref message, delivery, clientId);
+        }
+
         internal void HandleIncomingData(ulong clientId, ArraySegment<byte> payload, float receiveTime)
         {
 #if DEVELOPMENT_BUILD || UNITY_EDITOR

com.unity.netcode.gameobjects/Runtime/Messaging/MessagingSystem.cs

@@ -352,7 +352,7 @@ private bool CanSend(ulong clientId, Type messageType, NetworkDelivery delivery)
             return true;
         }
 
-        internal unsafe int SendMessage<TMessageType, TClientIdListType>(ref TMessageType message, NetworkDelivery delivery, in TClientIdListType clientIds)
+        internal int SendMessage<TMessageType, TClientIdListType>(ref TMessageType message, NetworkDelivery delivery, in TClientIdListType clientIds)
             where TMessageType : INetworkMessage
             where TClientIdListType : IReadOnlyList<ulong>
         {
@@ -367,6 +367,12 @@ internal unsafe int SendMessage<TMessageType, TClientIdListType>(ref TMessageTyp
 
             message.Serialize(tmpSerializer);
 
+            return SendPreSerializedMessage(tmpSerializer, maxSize, ref message, delivery, clientIds);
+        }
+
+        internal unsafe int SendPreSerializedMessage<TMessageType>(in FastBufferWriter tmpSerializer, int maxSize, ref TMessageType message, NetworkDelivery delivery, in IReadOnlyList<ulong> clientIds)
+            where TMessageType : INetworkMessage
+        {
             using var headerSerializer = new FastBufferWriter(FastBufferWriter.GetWriteSize<MessageHeader>(), Allocator.Temp);
 
             var header = new MessageHeader
@@ -426,6 +432,13 @@ internal unsafe int SendMessage<TMessageType, TClientIdListType>(ref TMessageTyp
             return tmpSerializer.Length + headerSerializer.Length;
         }
 
+        internal unsafe int SendPreSerializedMessage<TMessageType>(in FastBufferWriter tmpSerializer, int maxSize, ref TMessageType message, NetworkDelivery delivery, ulong clientId)
+            where TMessageType : INetworkMessage
+        {
+            ulong* clientIds = stackalloc ulong[] { clientId };
+            return SendPreSerializedMessage(tmpSerializer, maxSize, ref message, delivery, new PointerListWrapper<ulong>(clientIds, 1));
+        }
+
         private struct PointerListWrapper<T> : IReadOnlyList<T>
             where T : unmanaged
         {