Thread on SBCL development mailing list: Coroutines, goroutines

https://sourceforge.net/p/sbcl/mailman/sbcl-devel/thread/CACxje59P1B3-0ci%3D3izZJ2Do1%2Bj9ENTuQkP1DU3E64OYtnOtyg%40mail.gmail.com/#msg59301073