Async prover work-around

[Mirko-von-Leipzig]

The proving service currently enables the async feature of base which clashes with our usage of it.

See if we can work-around this by changing our usage to async.

[Mirko-von-Leipzig]

A basic attempt of this failed due to non-send futures in the proving service implementation.

I suspect a deeper refactoring/simplification of the service would be required, though maybe its a case of me holding it wrong.

[sergerad]

Keen to take a look. Might be related or loosely related to the Client Send / Sync issue which I'm planning on getting back to.

[sergerad]

Just keeping this issue up to date based on the PR / comments, see here.

TLDR

• The most imminent issue is that winter maybe_async always results in futures that are not Send.
• Even if we patch maybe_async to allow for Send futures, there are trait objects that cause Send/Sync problems in other parts of the miden stack.
• This issue will be unblocked when we address the Send/Sync issues more broadly.

[sergerad]

@Mirko-von-Leipzig AFAICT we can close this since the maybe_async removal work. I don't see any async feature flags in base or note anymore.

[Mirko-von-Leipzig]

Closed by #1122