re-export async-attributes

[yoshuawuyts]

Closes #237. The docs don't render properly on this, but I think that's okay. Thanks!

[yoshuawuyts]

This PR and async-rs/async-attributes#8 have been updated to now use the attributes feature as suggested in #438.

I think merging this would actually be really nice, as we enable people to write some nicer-looking applications the way they could with Runtime, but we don't lose any performance in the base case. Coupled with the runtime feature I think async-std will be a really well rounded option for almost every use!

Screenshots

[ghost]

Are these now stable attributes? I assume so and fine with that, but just making sure it's not an oversight. :)

There's not much we can do wrong with these attributes - they're pretty straightforward, right?

[ghost]

Approving, but let's wait for @skade to also take a look.

[yoshuawuyts]

There's not much we can do wrong with these attributes - they're pretty straightforward, right?

Not necessarily, and I think we should be cautious. async-rs/async-attributes#11 and async-rs/async-attributes#9 actually should be resolved first.

edit: I don't think we should be exposing that particular API. So another option is we punt #[bench] until we figure it out and only expose #[test] and #[main]. Those two could be insta-stable for sure.

[yoshuawuyts]

Updated the PR to be exactly that. Thanks!

[ghost]

Agree with everything you said 👍

[ghost]

ping for @skade

[yoshuawuyts]

@stjepang I would like to make this available in the next release; I'd like to propose we merge this.