Ruby has fibers, though up until recently they weren't used much for anything, except lazy iteration. Recent efforts have built on fibers to provide concurrency

Ruby has fibers, though up until recently they weren't used much for anything, except lazy iteration. Recent efforts have built on fibers to provide concurrency with non-blocking I/O: https://github.com/socketry/async https://github.com/socketry/async https://github.com/digital-fabric/polyphony https://github.com/digital-fabric/polyphony Disclaimer: I'm the author of Polyphony.