[igregoryca]

Hm. You and parent comment have made me realize something: as much as I dislike how many useful abstractions are missing from Go, async for blocking syscalls is not one of them, since the "green thread" model effectively makes all functions async for the purposes of blocking syscalls. So I retract my "you have to do it manually" comment in this case. I guess that's part of why people love Go's concurrency.

Of course, as you said, stackful coroutines come with runtime overhead. But that's the tradeoff, and I'm sure they are substantially more efficient (modulo FFI calls) than the equivalent async-everywhere code would be in typical JS or Python runtimes.

My "you have to do it manually" comment comes from some other peeves I have with Go. I guess the language designers were just hyper-focused on syscall concurrency and memory management (traditionally hard problems in server code), because Go does fare well on those specific fronts.