code: def worker_main(self):
          
          self._setup_master()
          self._setup_services()
  
          try:
              # Let the parent know our listening socket is ready.
              mitogen.core.io_op(self.child_sock.send, b('1'))
              # Block until the socket is closed, which happens on parent exit.
              mitogen.core.io_op(self.child_sock.recv, 1)
          finally:
              self.broker.shutdown()
              self.broker.join()
  
              # Test frameworks living somewhere higher on the stack of the
              # original parent process may try to catch sys.exit(), so do a C
              # level exit instead.
              os._exit(0)
docs: The main function of for the mux process: setup the Mitogen broker
          thread and ansible_mitogen services, then sleep waiting for the socket
          connected to the parent to be closed (indicating the parent has died).