Feature: Adapter trait with optional async

[Totodore]

Make a version of the adapter trait async. This will allow remote adapter implementation (e.g redis adapter, mongodb adapter).

[Shorakie]

does the maybe_async crate cut it?

[Totodore]

Yes, it is a good idea, but it implies to also apply maybe_async on Operators and Socket structs to maybe return futures from the adapter.

[ElijahJohnson5]

This would be awesome to have! Really enjoy the work you are doing on this

[headironc]

I think there may be scenes that require both async and sync.

[Totodore]

Sure, the compatibility with previous sync code and the possibility to use both are my main blocking points to move on on this feature.
Currently one of the approaches I considered is using Operators to express multi-node async code and keep sync operations on emit/room/ns by default.

socket.emit("test", ()); // default sync behavior that will emit only from this node.
socket.async().emit("test", ()).await; // async behavior shared between nodes.

Other possibilities are:

• to use feature flags to transform all sync function to async when enabling the async feature on but it would break the default sync feature and features should always be additive for these reasons.
• To remove sync possibilities on emit/rooms/ns functions and to have everything async by default.