issue: publish future hangs when a context manager is not used

[anguillanneuf]

Do we want to support both?

# This works.
with make_publisher(topic_path) as publisher_client:
    api_future = publisher_client.publish(data.encode("utf-8"))
    ack_id = api_future.result()

# This hangs.
publisher_client = make_publisher(topic_path)
api_future = publisher_client.publish(data.encode("utf-8"))
ack_id = api_future.result()

[dpcollins-google]

No. This is WAI. You need to call __enter__() on the publisher. You can always do so manually by calling publisher_client.__enter__(), but you need to call it.

[anguillanneuf]

I can add a comment in the sample. However, is this clear in the library documentation anywhere?

[dpcollins-google]

This should be clear from the fact that it overrides ContextManager, but I can add an additional comment documenting this.