message: update _socket->nonblock field
diff: @@ -454,6 +454,7 @@ PHP_FUNCTION(swoole_event_add)
  swConnection *socket = swReactor_get(SwooleG.main_reactor, socket_fd);
  socket->object = reactor_fd;
  socket->active = 1;
  + socket->nonblock = 1;
  RETURN_LONG(socket_fd);
  }
  