Coroutines are cooperative scheduling, and have all the same drawbacks. They're really really good for high performance proxies though, since they make a very

Coroutines are cooperative scheduling, and have all the same drawbacks. They're really really good for high performance proxies though, since they make a very small number of cheap decisions for each request, and then punt the bit shuffling to the OS (which uses threads). These proxies are ubiquitous and well regarded (nginx, haproxy, linkerd, etc) so they take up maybe more mind share than they should.