超级群组，消息 notLoaded 时，返回值为默认值的对应消息对象。使用时，需要先判断消息是否 loaded'

Author: imndx

client/src/main/java/cn/wildfirechat/client/ClientService.java

@@ -4222,6 +4222,9 @@ public MessageContent messageContentFromPayload(MessagePayload payload, String f
         }
 
         MessageContent content = contentOfType(payload.type);
+        if(payload.notLoaded > 0){
+            return content;
+        }
         try {
             if (content instanceof CompositeMessageContent) {
                 ((CompositeMessageContent) content).decode(payload, this);