Io_uring, kTLS and Rust for zero syscall HTTPS server

So, current status on async

Rust - you need to understand: Futures, Pin, Waker, async runtimes, Send/Sync bounds, async trait objects, etc.

C++20, coroutines.

Go, goroutines.

Java21+, virtual threads

Note that C++ coroutines use heap allocation to avoid the problems that Pin is solving, which is a pretty big carve-out from the "zero overhead principle" that C++ usually aims for. The long development time of async traits has also been related to Rust not heap allocating futures. Whether that performance+portability-vs-complexity tradeoff is worth it for any given project is, of course, a different question.