code: def start(self, start_loop=True):
          
          txaio.start_logging()
          runner = self.setup_runner()
          if start_loop:
              try:
                  runner.run(Component)
              except EventifyHandlerInitializationFailed as initError:
                  logging.error('Unable to initialize handler: %s.' % initError.message)
                  sys.exit(1)
              except ConnectionRefusedError:
                  logging.error('Unable to connect to crossbar instance. Is it running?')
                  sys.exit(1)
              except KeyboardInterrupt:
                  logging.info('User initiated shutdown')
                  loop = asyncio.get_event_loop()
                  loop.stop()
                  sys.exit(1)
              self.check_event_loop()
              self.reconnect()
          else:
              return runner.run(
                  Component,
                  start_loop=start_loop
              )
docs: Start a producer/consumer service