[pjmlp]

They don't work just fine in C#, there is a reason why one of ASP.NET architects has written a guide of best practices.

https://github.com/davidfowl/AspNetCoreDiagnosticScenarios/b...

Ironically, C++'s design is heavily related to C#, as the initial proposal was done by Microsoft and shares many of the same ideas, including how to create runtime aware awaitable types.

[captainmuon]

I've never used ASP.NET, I mean they work fine in GUI apps where you click a button, start downloading a file, and then show a message when the file has been downloaded.

Making code nonblocking without threads and without callbacks = happy case for async. Writing multithreaded servers focussed on throughput is a whole other can of worms, which is basically my point.