public void AddFriendChatMessageCallback(OnlineFriendChatDelegate callback)
 {
     if (!_friendChatCallbacks.Contains(callback))
     {
         _friendChatCallbacks.Add(callback);
     }
 }
 public void RemoveFriendChatMessageCallback(OnlineFriendChatDelegate callback)
 {
     _friendChatCallbacks.Remove(callback);
 }
 public void RemoveFriendChatMessageCallback(OnlineFriendChatDelegate callback)
 {
 }