I'm not saying that implementation doesn't matter. I'm saying that that there isn't a fundamental implementation difference "async" vs "threads". Threads are us

I'm not saying that implementation doesn't matter. I'm saying that that there isn't a fundamental implementation difference "async" vs "threads". Threads are used in both cases. It's a different choice of abstractions over the same underlying concepts. FYI, Rust (the language) has no concept of prioritising workloads; there is no async runtime in the language. Even with any of the async runtimes, workloads (i.e. tasks doing work) are prioritised by the OS. It's just threads executing code. Async runtimes are primarily concerned with the gaps between work, like waiting for I/O or other events.