Attempts to find the session id for a given topic

        http://crossbar.io/docs/Subscription-Meta-Events-and-Procedures/

async def lookup_session(self, topic_name):
        """
        Attempts to find the session id for a given topic

        http://crossbar.io/docs/Subscription-Meta-Events-and-Procedures/
        """
        res = await self.call("wamp.subscription.lookup", topic_name)
        self.log.info(res)