Me too, but I’d I realized that I’d rather the Swift team not half-ass such a big feature, especially when they’re working on ABI stability and translation of Foundation API’s.

Plus, I bet one of the things that’s holding proper concurrency back are Apple’s frameworks. I’d rather deal with callbacks for another year or two than use a rushed language feature.

Concurrency is done with libdispatch library, which is also open source. Right now, it's only compatible with OS X, but int their post, they said that "For Linux, Swift 3 will also be the first release to contain the Swift Core Libraries."

https://swift.org/blog/swift-3-0-release-process/