androidx.datastore integration

The Android team is quietly working on a SharedPreferences replacement called datastore. It’d be nice to have a module that wraps that, once it’s ready. An interesting wrinkle is that it has fully coroutine-based APIs so it’s going to be non-trivial to wrap with the existing Settings interface.

[russhwolf]

My current thinking is to have both FlowSettings and SuspendSettings interfaces, and converters between them and the standard Settings and ObservableSettings. Any Settings implementation can be wrapped to SuspendSettings pretty easily, but FlowSettings can only wrap around ObservableSettings because you need to set a listener to be able to get new updates in its Flows. There would be DataStore implementations of both, so you could use the one that fits your use-case better depending on what other implementations you need interop with.

I want to have a version of this ready in the near future as part of 0.7

[russhwolf]

Flow would be nice (there’s a prototype in #37 of wrapping flows around the existing listeners) but I’m leaning toward suspend fun by default so that commonality with non-observable implementations (in particular, JS) is easier. Still need to do more thinking and prototyping though.