feat: Add AsyncBacktraceLayer to allow users dump this execution tree at runtime

[Xuanwo]

https://github.com/tokio-rs/async-backtrace

Efficient, logical 'stack' traces of async functions.

#[async_backtrace::framed]
async fn pending() {
    std::future::pending::<()>().await
}

#[async_backtrace::framed]
async fn foo() {
    bar().await;
}

#[async_backtrace::framed]
async fn bar() {
    futures::join!(fiz(), buz());
}

#[async_backtrace::framed]
async fn fiz() {
    tokio::task::yield_now().await;
}

#[async_backtrace::framed]
async fn buz() {
    println!("{}", baz().await);
}

[Xuanwo]

Similiar to #2616, but powered by async-backtrace.

[dqhl76]

Please /assign me!

[dqhl76]

It seems we cannot use async-backtrace to create a new layer.

#[async_backtrace::framed] will change the fn read 's signature.

impl<A: Accessor> LayeredAccessor for AsyncBacktraceAccessor<A> {
    ...
    #[async_backtrace::framed]
    async fn read(&self, path: &str, args: OpRead) -> Result<(RpRead, Self::Reader)> {
        self.inner.read(path, args).await
    }
    ...
}

The example code below will give an error Not all trait items implemented, missing: read [E0046]

[Xuanwo]

It's a bit strange. Could you create a draft PR so that we can identify the root cause?