Opens the connection.

        An open connection will monitor for disconnects from the remote end.
        Messages are either received as replies to outgoing messages, or
        received from an incoming queue.

def open(self):
        """Opens the connection.

        An open connection will monitor for disconnects from the remote end.
        Messages are either received as replies to outgoing messages, or
        received from an incoming queue.
        """
        LOGGER.info('Connecting to %s', self._url)
        asyncio.ensure_future(self._do_start())