long essay about coroutine philosophy(!) that I just saw https://www.chiark.greenend.org.uk/~sgtatham/quasiblog/coroutines-philosophy/
(I'd seen Simon's site before just for that C preprocessor hack -- I didn't realize his site is so actively updated and that he'd added these other pages about C++20 and coroutine philosophy)
@omar he’s on here too, as @simontatham!