docs: def _recv_callback(self, msg):
          """
          Method is called when there is a message coming from a Mongrel2 server.
          This message should be a valid Request String.
          """
          m2req = MongrelRequest.parse(msg[0])
          MongrelConnection(m2req, self._sending_stream, self.request_callback,
              no_keep_alive=self.no_keep_alive, xheaders=self.xheaders)