Close the connection.

        Returns True so it is suitable as an `~MockupDB.autoresponds` handler.

def hangup(self):
        """Close the connection.

        Returns True so it is suitable as an `~MockupDB.autoresponds` handler.
        """
        if self._server:
            self._server._log('\t%d\thangup' % self.client_port)
        self._client.shutdown(socket.SHUT_RDWR)
        return True