The idea of using coroutines for asynchronous programming is quite old actually. ML has used it since the 80s [1]. Python itself had it way before C# with Twist

The idea of using coroutines for asynchronous programming is quite old actually. ML has used it since the 80s [1]. Python itself had it way before C# with Twisted's inlineCallbacks [2]. What C# (actually it was F#) introduced was the specific 'await' and 'async' syntax keywords. Those are being copied in other languages, and they're just sugar over coroutines. [1] http://www.cambridge.org/gb/academic/subjects/computer-science/distributed-networked-and-mobile-computing/concurrent-programming-ml http://www.cambridge.org/gb/academic/subjects/computer-scien... [2] http://blog.mekk.waw.pl/archives/14-Twisted-inlineCallbacks-and-deferredGenerator.html http://blog.mekk.waw.pl/archives/14-Twisted-inlineCallbacks-...