从cloud pubsub确认/处理我的所有消息都需要超过600秒的时间限制，因此，在我处理消息时，我需要最多计算590秒，并请求将确认截止时间再延长600秒（这样其他订户就不会获得重新提交）。我的计划是编写一个 Package 器，等待处理运行并

while awaited processing_function not finished:
    update the deadline

我用于处理的基本代码：

subscriber = pubsub_v1.SubscriberClient()
subscription_path = "projects/path/to/subscription"

def callback(message):
    print(f'Received message: {message}')
    print(f'data: {message.data}')

    if message.attributes:
        # PROCESS THAT'S GOING TO TAKE A LONG TIME
        # ...

    message.ack()

# subscribe method provides an asynchronous interface for processing its callback

streaming_pull_future = subscriber.subscribe(subscription_path, callback=callback)
with subscriber:                                           # wrap subscriber in a 'with' block to automatically call close() when done
    try:
        streaming_pull_future.result()                          # going without a timeout will wait & block indefinitely
    except TimeoutError:
        streaming_pull_future.cancel()                          # trigger the shutdown
        streaming_pull_future.result()

我如何实施计划，不断更新截止日期，直到回调运行完毕？我在asyncio方面不是很有经验。我甚至可以有一个 Package 器函数来等待回调，并在等待时作为后台进程运行while循环吗？