implement embedded-hal-async traits using maybe-async-cfg

[hdoordt]

Fixes #30

To do:

• Add usage example in README
• Add usage example in rustdoc
• Add example for microbit v2
• Fix errors caused by #[doc = include_str!("delay.md")]'
• [ ] Test async stuff

[hdoordt]

I don't think we actually want this. However, fixing the warning is going to take writing a bunch of boilerplate, I'm afraid

[eldruin]

I agree and would leave it as-is.

[eldruin]

Looks good to me so far, thank you!

[eldruin]

Could you also update the MSRV to Rust 1.75.0 and add a note about it in the changelog? Then the CI should stop complaining.

[hdoordt]

@eldruin I'm having some trouble getting the tests to run for async. Here's my current attempt: hdoordt@ded90ca

Sadly, the attributes don't seem to work together all that well. Can you maybe have a look?

[eldruin]

The tests themselves in hdoordt@ded90ca work fine for me after adding a single .await in accel_mode_and_odr.rs:297 and running cargo test --features='async' --lib.
However, the doctests and example cannot be compiled due to linux-embedded-hal not supporting async. That is expected and I would not try to do anything about it.
It is very interesting to be able to run async tests but honestly I would not have put the effort into it since the code is so far the same.

[eldruin]

The micro:bit example looks great :)

[hdoordt]

The tests themselves in hdoordt@ded90ca work fine for me after adding a single .await in accel_mode_and_odr.rs:297 and running cargo test --features='async' --lib. However, the doctests and example cannot be compiled due to linux-embedded-hal not supporting async. That is expected and I would not try to do anything about it. It is very interesting to be able to run async tests but honestly I would not have put the effort into it since the code is so far the same.

Problem is that now the sync tests don't work anymore. I'll leave the async testing out if it's all the same to you.

However, the test coverage is regressing, which makes CI fail.

[eldruin]

Looks great. Just one trivial thing left: Could you fix the code formatting?

[hdoordt]

Done and done.

Could you create a release that includes this feature to crates.io? I'd like to use the driver in a training.

[eldruin]

Great work, thank you!

[eldruin]

I have released this in version 1.1.0.
I have also removed the microbit-example feature, since we are not running the tests with async and async is a requirement for the example. Let me know if that is a problem for you.