Rust Trait enhancements

[coder137]

Required for this project

• Tracking issue for impl Trait in const and static items and let bindings rust-lang/rust#63065
• Tracking Issue for async_fn_in_trait, return_position_impl_trait_in_trait rust-lang/rust#91611

Reference

https://github.com/rust-lang/rust/labels/S-tracking-impl-incomplete

91611

Return impl trait in traits

pub trait AsyncGpioIn {
    fn poll_read(&self, trigger: GpioValue) -> impl Future<Output = ()>;
}

Marking trait methods async

pub trait AsyncGpioIn {
    async fn poll_read(&self, trigger: GpioValue);
}