code: def start(self, blocking=True):
          
          self.setup_zmq()
          if blocking:
              self.serve()
          else:
              eventlet.spawn(self.serve)
              # ensure that self.serve runs now as calling code will
              # expect start() to have started the server even non-blk
              eventlet.sleep(0)
docs: Start the producer.  This will eventually fire the ``server_start``
          and ``running`` events in sequence, which signify that the incoming
          TCP request socket is running and the workers have been forked,
          respectively.  If ``blocking`` is False, control .