check deadline before sendMsg, because select is randomly, sometimes it will write successfully after deadline

Signed-off-by: Asutorufa <[email protected]>

Author: Asutorufa

session.go

@@ -487,6 +487,8 @@ func (s *Session) sendMsg(hdr header, body []byte, deadline <-chan struct{}) err
 	select {
 	case <-s.shutdownCh:
 		return s.shutdownErr
+	case <-deadline:
+		return ErrTimeout
 	default:
 	}