code: def auto_unsubscribe(self, sid, limit=1):
          
          if self.is_draining:
              raise ErrConnectionDraining
          yield self._unsubscribe(sid, limit)
docs: Sends an UNSUB command to the server.  Unsubscribe is one of the basic building
          blocks in order to be able to define request/response semantics via pub/sub
          by announcing the server limited interest a priori.