[DRAFT] Add async/await support for oxide-auth-async

[FrancisMurillo]

This changes/fixes/improves …

• I have read the [contribution guidelines][Contributing]
• This change has tests (remove for doc only)
• This change has documentation
• Corresponds to issue ([QUESTION] How to integrate oxide_auth_async and oxide_auth_actix? #163)

Still fixing the main example work and adding another example to show explicit async/await usage

I license past and future contributions under the dual MIT/Apache-2.0 license, allowing licensees to chose either at their option.

[197g]

On a general note: I'd actually rather replace the actix bindings with fully asynchronous ones rather than have two separate packages for it, if that sounds appropriate.

[FrancisMurillo]

On a general note: I'd actually rather replace the actix bindings with fully asynchronous ones rather than have two separate packages for it, if that sounds appropriate.

I tried doing in a separate crate first to see if there might be any issues with types and compatibility. I did have a problem with the actix actor example since the current implementation of Generic kinda needs to be Clone-able to pass the compiler check.

[FrancisMurillo]

@HeroicKatora So this is kinda my async use case. (Mine was diesel but wrapped them in async domain methods.) I think you can inspect the current example while I try to make the original example with Generic work if possible.

[FrancisMurillo]

@HeroicKatora Okay, I have tried several attempts to make Generic work within the async actix handler but its kinda tricky without creating thread safe versions generic components or removing the &mut in every Endpoint method which I do not think is ideal. So my current example I think is the easiest way I found so far.

[ConcurrentSquared]

I don't want to bother anyone here (this PR is obviously inactive), but I do have a updated fork of this PR with some very small improvements (the largest being the addition of the async ClientCredentials OAuth operation).

However, it should be noted that my fork is only for a personal side-project; I will almost certainly will not submit my own PR (or try to help with this PR), as I do not feel like I have either the time or experience (in Rust or in OAuth) to help in any significant way.