Return query ID before query completes

[johallar]

Feature proposal

The query method of the API currently returns a Promise of a PrestoQuery object, but in certain cases (longer running queries particularly) a user may want to have the query ID returned first so they can look up query info as it's running.

I propose adding an additional query method (could be implemented as an async generator), first returning the query ID, and then returning the PrestoQuery response before completing. Would love to hear thoughts, and I would be happy to help implement that solution as well!

[johallar]

I created a draft PR of a possible implementation, still needs work, but mentioned it above for discussion

[alonsovb]

Thanks @johallar , yeah, this is a very common use case, thanks for the suggestion and the PR.

As long as we keep the original query method and signature I think we're good.

Let me know when you think the PR is ready for review and I'll take a look

[johallar]

@alonsovb Just took this PR out of draft. I implemented it so that the generator returns the first response and then the results, but could see an argument for yielding results after each request, let me know what you think. Also added some unit tests for the client.

[alonsovb]

Thanks for the contribution @johallar . I'll check if we can do a new publish after merging it.