In Unix you don't get a choice to block on one or the other. You just get a non-blocking File Descriptor. To add this you'd need to iron bandage system calls d

In Unix you don't get a choice to block on one or the other. You just get a non-blocking File Descriptor. To add this you'd need to iron bandage system calls during compilation depending on which calls were made, and their order they were made. The alternative is having an Epoll/Kqueue loop run until one or another happen. But that's still a lot of magic and resource consumption behind the scenes for a language that offers low level control.