Venice (a.k.a. SwiftGo)
Paulo Faria (via iOS Dev Weekly):
Venice is a pure Swift/C library that provides CSP for Swift 2.
[…]
Venice is fast because the coroutines are light coroutines managed by libmill instead of threads managed by the OS. The Chinese Whispers example in the command line application shows how you can create up to 100.000 concurrent coroutines (tested in a 8 GB MacBook Pro early 2015).
That’s Communicating Sequential Processes (CSP), like in Go, rather than Continuation-Passing Style (CPS).