Introduce `Timed` to track how long a future is alive for

[narwhaljs]

This aims to add a simple feature that allows users to easily track how long a future was alive for. It attempts to follow all standards similar to Timeout. It can be constructed manually through the tokio::time::timed() function, or through the extension trait allowing any_future to call any_future.timed().

Motivation

Are you tired of writing:

let now = std::time::Instant::now();
do_some_async_work().await;
let elapsed = now.elapsed();
println!("Finished some async work in {elapsed:?}");

Solution

Now you can write:

let (_, elapsed) = do_some_async_work().timed().await;
println!("Finished some async work in {elapsed:?}");

[mox692]

Hmm, I think other crates can provide similar features, so I'm not sure if we should include this in tokio.

[narwhaljs]

Hmm, I think other crates can provide similar features, so I'm not sure if we should include this in tokio.

Yeah i think futures is probably a better spot for it, or any other ideas? Or is there something that does this already? Fine to close this. It did feel like it slotted decent into the time feature of tokio though but i agree its fairly generic.

[mox692]

I believe it's generally better not to include functionality in tokio that can be implemented in other crates.

[ADD-SP]

I'm also not inclined to add this feature into tokio, This feature is more related to observability things, not the async runtime itself.

[ADD-SP]

https://crates.io/crates/future-timing/0.1.0

There is a crate provides similar features.

I closed this PR based on our discussion, thanks for your contribution.