Replace async_trait with native async fns

[gahag-cw]

Note that the usage of CustomizeConnection requires it to be object safe, and thus we need to use boxed futures instead of plain async fns.

[gahag-cw]

@djc we have an issue with the coverage pipeline:

There was an error running the uploader: Error uploading to [https://codecov.io:](https://codecov.io/) Error: There was an error fetching the storage URL during POST: 429 - {"message":"Rate limit reached. Please upload with the Codecov repository upload token to resolve issue. Expected time to availability: 2144s."}

[djc]

This mostly looks good to me. Please squash into two commits:

1. MSRV bump
2. All the code changes

[djc]

Can we spell this <'r, 'a: 'r, 'b: 'r> instead? And do we really need the 3 separate lifetimes?

Why is BoxFuture useful? Could we just do Box<dyn Future<..>> instead?

[gahag-cw]

BoxFuture<'a, T> is actually Pin<Box<dyn Future<Output = T> + Send + 'a>>. I'll apply the suggestions.

[gahag-cw]

And do we really need the 3 separate lifetimes?

I'm not sure, but that's what async_trait generated, so I kept it to prevent further breaking changes in the API.

[djc]

I think #231 has solved the coverage issue, please rebase on top of current main.

[gahag-cw]

@djc I applied the following suggested changes:

• squash into MSRV bump and code changes commits
• change on_acquire lifetimes to <'r, 'a: 'r, 'b: 'r>
• replace all usages of BoxFuture<'r, Result<(), Error>> with Pin<Box<dyn Future<Output = Result<(), Error>> + Send + 'r>>

Let me know if you have any further suggestions.

[djc]

Please also add a separate commit that bumps all the version numbers.

[gahag-cw]

@djc done.

[djc]

Thanks!

[djc]

• Published bb8 v0.9.0 at registry crates-io
• Published bb8-postgres v0.9.0 at registry crates-io
• Published bb8-redis v0.18.0 at registry crates-io
• [new tag] v0.9.0 -> v0.9.0
• Release notes