code: def _sync(pack):
      
      task_queue = Queue()
      result_queue = Queue()
      task = SignedPackage.loads(pack)
      task_queue.put(task)
      task_queue.put('STOP')
      worker(task_queue, result_queue, Value('f', -1))
      result_queue.put('STOP')
      monitor(result_queue)
      task_queue.close()
      task_queue.join_thread()
      result_queue.close()
      result_queue.join_thread()
      return task['id']
docs: Simulate a package travelling through the cluster.