make everything async

[gregdhill]

Signed-off-by: Gregory Hill gregorydhill@outlook.com

This still requires some work, but I wanted to open a PR to assess interest - perhaps this belongs in a separate repository.

Uses the reqwest library to perform async http requests and async-trait to support async traits.

[stevenroose]

Awesome, this has been on our wishlist for a while!

Some questions:

• (1) did you consider contributing to the jsonrpc crate and implement async functionality there first as well?
• (2) I'd like to keep using non-async as a possibility. How would you feel about having a compile feature and duplicating all methods, a sync and async variant? That would also make that we can keep the integration test simpler by keeping it sync.

[stevenroose]

Is it possible to drop this dependency by just writing the functions more verbose using Future?

[elichai]

You mean Pin<Box<dyn Future<...> + Send +'_>> (https://smallcultfollowing.com/babysteps/blog/2019/10/26/async-fn-in-traits-are-hard/)

[gregdhill]

I think it may be a little bit more involved, see: https://github.com/dtolnay/async-trait#explanation

[gregdhill]

• (1) That would make sense, I will look into it.
• (2) Possibly, of course any async method can be run synchronously. Is there a benefit to a distinct separation?

[sgeisler]

I'd like to keep using non-async as a possibility

@stevenroose BDK has implemented something like that (usage example). Maybe we could use that too?

[stevenroose]

I'd like to keep using non-async as a possibility

@stevenroose BDK has implemented something like that (usage example). Maybe we could use that too?

How does that work? Does it automatically add both async and sync methods on the traits?

[sgeisler]

How does that work? Does it automatically add both async and sync methods on the traits?

To me it looks like they generate two versions of each function and activate only one depending on a feature flag. It's maybe a bit too much magic, idk. So you have to decide to go full async or not.