Support for async closure

[not-elm]

Since Rust 2024 edition, We can use async-closures withAsyncFn* traits.
By using this feature, we will be able to write code like the example below.

Reactor::schedule(async move |task|{

});

However, the future returned by the closure cannot be made thread-safe, which makes the implementation difficult (it is technically doable if you use an unsafe impl, though).

    #[inline(always)]
    pub fn schedule<F>(f: F) -> Scheduler<State>
    where
        F: AsyncFnOnce(CoreTask<State>) + Send + Sync + 'static,
        <F as AsyncFnOnce<(CoreTask<State>,)>>::CallOnceFuture: Send + Sync,
       ---------------------------------------------- expected 1 generic argument