docs: def __bind(self):
          '''
          Bind to the local port
          '''
          # using ZMQIOLoop since we *might* need zmq in there
          install_zmq()
          self.io_loop = ZMQDefaultLoop()
          self.io_loop.make_current()
          for req_channel in self.req_channels:
              req_channel.post_fork(self._handle_payload, io_loop=self.io_loop)  # TODO: cleaner? Maybe lazily?
          try:
              self.io_loop.start()
          except (KeyboardInterrupt, SystemExit):
              # Tornado knows what to do
              pass