pubsub: allow setting a pull HTTP timeout

[yarharel]

What I would like to do is be able to send a timeout param in the pull request to tell pubsub to send back a response after a 30000ms (or something else) if no messages are published during that time.

Exactly the same issue as in Node:
googleapis/google-cloud-node#981

[tseaver]

This would involve adding a timeout option to the _gax._SubscriberAPI.subscription_pull method (similar to the one added to _gax._PublisherAPI.topic_publish method in deca383), and surfacing that option at the subscription.Subscripton level (Topic.publish needs to expose the timeout too).

[lukesneeringer]

Hello! :-)
First, a mea culpa; I have not done as good of a job at keeping up with issues as I should have. If you are getting this (I admit it) cut and paste, it is likely because your issue sat for too long.

In this case, I have been in the process of making a radical update to the PubSub library (#3637) to add significant performance improvements and a new surface, which we hope to launch soon. As such, I am clearing out issues on the old library. It is my sincere goal to do a better job of being on top of issues in the future.

As the preceding paragraph implies, I am closing this issue. If the revamped library does not solve your issue, however, please feel free to reopen.

Thanks!