[biorach]

I find the developer experience is quite different. Which is actually quite important. In the async runtimes I am familiar with I find managing shared resources and locking much easier.

But maybe I'm missing something here. Do you know of an async runtime and a threaded runtime that do not have significant differences?

[gpderetta]

Take boost.asio: it is a generic event loop (that can run on one or more OS threads): on top of asio you can run old school manual continuation passing code, promise/future based code, async code using C++20 coroutines (or a macro hack), or more classically multithreaded code using boost.context. You can write the same logical code in any style and the transformation is fairly mechanical.