Windows-rs: Support for async

[kennykerr]

Need to integrate Rust's async-await support with WinRT's async support via its IAsyncXxx interfaces.

[Boddlnagg]

I have a proof-of-concept prototype implementation for winrt-rust in the branch https://github.com/Boddlnagg/winrt-rust/tree/futures-preview ... maybe this helps ;-)

[handicraftsman]

Whoever implements this, make sure its compatible with tokio please.

[eklipse2k8]

error[E0277]: the trait bound `std::result::Result<windows::foundation::IAsyncOperation<windows::devices::enumeration::DeviceInformationCollection>, winrt::error::Error>: core::future::future::Future` is not satisfied
  --> src\lib.rs:18:20
   |
18 |     let _devices = DeviceInformation::find_all_async_device_class(DeviceClass::AudioCapture).await;
   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `core::future::future::Future` is not implemented for `std::result::Result<windows::foundation::IAsyncOperation<windows::devices::enumeration::DeviceInformationCollection>, winrt::error::Error>`

[bdbai]

@eklipse2k8 there should be a ? before .await operator

[kennykerr]

@eklipse2k8 Support for .await hasn't been implemented yet.