docs: def _recv_msg(self):
          """Read a message from the server."""
          command = ord(recv_blocking(self._soc, 1))
          msglen = recv_blocking(self._soc, 4)
          msglen = ((msglen[0] << 24) + (msglen[1] << 16) +
                    (msglen[2] << 8) + msglen[3])
          msg = recv_blocking(self._soc, msglen)
          return command, msg