Run the event loop once.

def event_loop(self):
        """ Run the event loop once. """
        if hasattr(self.loop, '._run_once'):
            self.loop._thread_id = threading.get_ident()
            try:
                self.loop._run_once()
            finally:
                self.loop._thread_id = None
        else:
            self.loop.call_soon(self.loop.stop)
            self.loop.run_forever()