Add NetworkReplicator.AddObjectIdMapping for global/custom network objects sync

#3042

Source/Engine/Networking/NetworkReplicator.h

@@ -122,6 +122,13 @@ public:
     /// </summary>
     /// <param name="objectId">The network object identifier to map. Contains result ID once the method completes.</param>
     API_FUNCTION() static void MapObjectId(API_PARAM(Ref) Guid& objectId);
+
+    /// <summary>
+    /// Adds a new mapping for object identifier. Can be used to link locally-spawned object with across different clients.
+    /// </summary>
+    /// <param name="obj">The network object.</param>
+    /// <param name="objectId">The network object identifier to use (eg. defined by server or global/static).</param>
+    API_FUNCTION() static void AddObjectIdMapping(const ScriptingObject* obj, API_PARAM(Ref) const Guid& objectId);
 	
     /// <summary>
     /// Resolves foreign Guid into a local ScriptingObject