Snapshot method for async collections

[Kyzegs]

Is there a reason why the async collections do not have on_snapshot? And are there any plans to add this?

[tseaver]

@Kyzegs You ask a good question. I believe that the design of Collection.on_snapshot / Query.on_snapshot (start a background thread which invokes a callback thread "forever" or until cancelled) wasn't seen as a great fit for the current async pattern: in the async world, one would likely expect instead to have an async method which yielded the "snapshot" objects (sets of added / updated / removed / deleted documents).

[tseaver]

Note that adding async support for the Watch mechanism is an existing feature request: #131