Dealing with cancel safety in async Rust

[mgeisler]

I stumbled upon https://rfd.shared.oxide.computer/rfd/400 today and really liked it! The examples of cancel safety are great and easy to understand. In particular, I find

        for value in strings {
            tokio::select! {
                res = sender.send(value) => {
                    if res.is_err() {
                        println!("receiver closed");
                        break;
                    }
                }
                _ = interval.tick() => {
                    println!("interval tick");
                }
            }
        }

easy to reason about: I know that value is a String, so it's intuitive to me that sender.send(value) moves value out of my scope. Given that, it's very clear that if sender.send(value) returns a future which is dropped, well then value is gone.

Perhaps we could simplify our example to something similar?

Cc @mauvealerts and @djmitche who I think were the main authors of Pitfalls: Cancellation. Thanks @sunshowers for the article!

[sunshowers]

Want to mention that this was made public as part of my talk on async cancellation at RustConf yesterday: https://github.com/sunshowers/cancelling-async-rust