> To get Pin stuff out of the way: it is indeed more complicated than it could be (because reverse compatibility etc), but when was the last time you needed to write a poll implementation manually?
Often. Pin and Poll contribute to the problem of having a two-tiered ecosystem: people who can use async and people who can contribute to async internals. That's a problem I'd love to see fixed.
This is one of the reasons we've spent such a long time working on things like async-function-in-trait (AFIT), so that traits like AsyncRead/AsyncBufRead/AsyncWrite/etc can use that rather than needing Pin/Poll. (And if you need to bridge to things using Poll, it's always possible to use Poll inside an async fn; see things like https://doc.rust-lang.org/std/future/fn.poll_fn.html .)
I agree wholeheartedly (and I'm not surprised that you of all people often write raw futures!). I want to push back on the "async rust bad/failure/not ready" meme because
- it's perfectly possible to be a successful user of the async ecosystem as it is now while building great software;
- this two-tiered phenomenon is not unique to Rust, JS and Python struggle with it just as much (if not more due to less refined and messier design). As an example, [1] is elegant, but complex, and I'm less sure it's correct compared to a gnarly async Rust future, because the underlying async semantics are in flux.
Of course I'd love for the remaining snags (like AFIT) to go away, and simplified Pin story or better APIs would be great, but this negativity around async Rust is just wrong. It's a massive success already and should be celebrated.
> I want to push back on the "async rust bad/failure/not ready" meme because
Absolutely; to be clear, I think async Rust has been a massive success, and has a lot of painfully rough edges. The rough edges don't invalidate the massive success, and the massive success doesn't invalidate the painfully rough edges.
Often. Pin and Poll contribute to the problem of having a two-tiered ecosystem: people who can use async and people who can contribute to async internals. That's a problem I'd love to see fixed.
This is one of the reasons we've spent such a long time working on things like async-function-in-trait (AFIT), so that traits like AsyncRead/AsyncBufRead/AsyncWrite/etc can use that rather than needing Pin/Poll. (And if you need to bridge to things using Poll, it's always possible to use Poll inside an async fn; see things like https://doc.rust-lang.org/std/future/fn.poll_fn.html .)