I feel like it's missing my point. Using a chainsaw is harder than using a manual saw, but if you need to cut many trees it's a lot more efficient to first learn how to use the chainsaw.

Now if you take the chainsaw without spending a second thinking about learning to use it, and start using it like a manual saw... no doubt you will find it worse, but that's the wrong way to approach a chainsaw.

And I am not saying that async is "strictly better" than all the alternatives (in many situations the chainsaw is inferior to alternatives). I am saying that it is a tool. In some situations, I find it easier to express what I want with async. In others, I find alternatives better. At the end of the day, I am the professional choosing which tool I use for the job.

Right but how do you expose your state machine and epoll logic to callers? As a blocking function? As a function that accepts continuations and runs on its own thread? Or with no interface such that anyone who wants to interoperate with you has to modify your state machine?

And that was intuitive and easy to learn?

Not true. I’ve used both, and I often prefer the explicitness of async await. It’s easier to reason about. The language guarantees that functions which aren’t async can’t be preempted - and that makes a lot of code much easier to write because you don’t need mutexes, atonics and semaphores everywhere. And that in turn often dramatically improves performance.

At least in JS. I don’t find async in rust anywhere near as nice to use. But that’s a separate conversation.