Add shutdown options for the client classes

[feywind]

We are planning to add updates to the close() methods to allow for a more deterministic shutdown process. This will take care of issues like these:

https://github.com/googleapis/nodejs-pubsub/issues/1860 https://github.com/googleapis/nodejs-pubsub/issues/1856 https://github.com/googleapis/nodejs-pubsub/issues/1665 https://github.com/googleapis/nodejs-pubsub/issues/1648

The three options boil down to this:

• Wait for everything to finish dequeuing
• Bail immediately (and maybe return IDs of things that were pending)
• Nack everything in the queue and wait for those to send

[modestaspruckus]

Hey, any update on this, when it's planned to have proper close method?

[mcasarrubios]

Hi @feywind, is there a time estimate planned for this? This is something we need to be able to do a graceful shutdown. Thanks in advance

[mcasarrubios]

For us, the ideal solution would be this point ‘Wait for everything to finish dequeuing’.

[feywind]

@mcasarrubios Thanks for the input. Right now you can already do the basic "wait for dequeue" using these methods:

• subscriber.close()
• topic.flush()

The extra thing we want to add is allowing options for how to handle outstanding data (e.g. drop everything on the floor and quit immediately).