def on_connection_open(self, connection):
        """This method is called by pika once the connection to RabbitMQ has
        been established.

        :type connection: pika.TornadoConnection

        """
        LOGGER.debug('Connection opened')
        connection.add_on_connection_blocked_callback(
            self.on_connection_blocked)
        connection.add_on_connection_unblocked_callback(
            self.on_connection_unblocked)
        connection.add_backpressure_callback(self.on_back_pressure_detected)
        self.channel = self._open_channel()
This method is called by pika once the connection to RabbitMQ has
        been established.

        :type connection: pika.TornadoConnection