[Pauan]

I'm curious what things you consider to be half-baked about Rust async.

I've used Rust async extensively for years, and I consider it to be the cleanest and most well designed async system out of any language (and yes, I have used many languages besides Rust).

[tel]

Async traits come to mind immediately, generally needing more capability to existentially quantify Future types without penalty. Async function types are a mess to write out. More control over heap allocations in async/await futures (we currently have to Box/Pin more often than necessary). Async drop. Better cancellation. Async iteration.

[Pauan]

> Async traits come to mind immediately,

I agree that being able to use `async` inside of traits would be very useful, and hopefully we will get it soon.

> generally needing more capability to existentially quantify Future types without penalty

Could you clarify what you mean by that? Both `impl Future` and `dyn Future` exist, do they not work for your use case?

> Async function types are a mess to write out.

Are you talking about this?

    fn foo() -> impl Future<Output = u32>

Or this?

    async fn foo() -> u32

> More control over heap allocations in async/await futures (we currently have to Box/Pin more often than necessary).

I'm curious about your code that needs to extensively Box. In my experience Boxing is normally just done 1 time when spawning the Future.

> Async drop.

That would be useful, but I wouldn't call the lack of it "half-baked", since no other mainstream language has it either. It's just a nice-to-have.

> Better cancellation.

What do you mean by that? All Futures/Streams/etc. support cancellation out of the box, it's just automatic with all Futures/Streams.

If you want really explicit control you can use something like `abortable`, which gives you an AbortHandle, and then you can call `handle.abort()`

Rust has some of the best cancellation support out of any async language I've used.

> Async iteration.

Nicer syntax for Streams would be cool, but the combinators do a good job already, and StreamExt already has a similar API as Iterator.