OnRecv 这函数理论上是多线程调用，客户端需要注意下
(event int32, operate int32, id int64, group int64, from int64, to int64, body string)
| 21 | type MessageHandler interface { |
| 22 | // OnRecv 这函数理论上是多线程调用，客户端需要注意下 |
| 23 | OnRecv(event int32, operate int32, id int64, group int64, from int64, to int64, body string) |
| 24 | |
| 25 | // OnError 连接被服务器断开，或其它错误 |
| 26 | OnError(msg string) |