[CJefferson]

If I’m using threads for each of my tasks, then why do I need async at all? I find mixing async and threads is messy, because it’s hard to take a lock in async code, as that blocks other async code from running. I’m sure this can be done well, but I failed when I tried.

[seabrookmx]

It depends what framework/language you're using.

It's messy in something like Python, but mostly transparent in C#. In C# you effectively are using async/await to provide M-N threading ala. GoLang, it's just different syntax.

OP references the C# method Task.WhenAll so they might be assuming other languages are equally capable.

[nemothekid]

You can map N-async tasks onto M-threads. This is essentially what Rust does, and if you squint this is how Go works as well.

A go routine is not that different from an async task, except the runtime inserts all the await points for you.