windows-rs: IAsync{Action,Operation}{WithProgress,} are not Send, so their impl Futures cannot be send across threads.

async fn win32_icon(path: &str) -> Result<WinRTImageStream> {
    let exe = StorageFile::get_file_from_path_async(path)
        .winrt_with_context(|| format!("Get exe in {}", path))?
        .await
        .winrt_with_context(|| "async of getting StorageFile")?;
    let thumb = exe
        .get_thumbnail_async_overload_default_size_default_options(ThumbnailMode::SingleItem)
        .winrt_with_context(|| "Get thumbnail of file with default options")?
        .await
        .winrt_with_context(|| "async of getting thumbail")?;
    Ok(WinRTImageStream::from(thumb))
}

The above code generates an impl Future as the output of the async fn that is not Send, since the underlying impl Futures for IAsync{Action,Operation}{WithProgress,} are not Send either. This greatly limits the use of winrt-rs async code as they will have to single-thread bound. Specifically, we can’t use the normal spawn functions of tokio, async_std etc as the Future is not Send, but instead will have to use something like spawn_local.