True, but combining them can be a pain. My current codebase in C++ has both posix threads (std::thread) and libuv event-driven code. They're both fine, but it's

True, but combining them can be a pain. My current codebase in C++ has both posix threads (std::thread) and libuv event-driven code. They're both fine, but it's a nuisance whenever they intersect. I can't drop libuv, because there's a nodejs VM inside. I can't drop std::thread, because some other libraries that do IO run synchronously. A universal M:N threading system with coroutines underlying everything means that both styles of code can happily coexist.