Speaking as a QEMU developer, I really don't like the coroutine use. They're a portability mess, they tend to expose bugs in dusty corners of the compiler, and

Speaking as a QEMU developer, I really don't like the coroutine use. They're a portability mess, they tend to expose bugs in dusty corners of the compiler, and they can be painful to debug around. I would much rather take a view that C is simply not a language with coroutines in it, and not try to retrofit them without explicit support from the compiler and runtime...