Concurrency is done with libdispatch library, which is also open source. Right now, it&#x27;s only compatible with OS X, but int their post, they said that &quot;For Linux, Swift 3 will also be the first release to contain the Swift Core Libraries.&quot;<p><a href="https:&#x2F;&#x2F;swift.org&#x2F;blog&#x2F;swift-3-0-release-process&#x2F;" rel="nofollow">https:&#x2F;&#x2F;swift.org&#x2F;blog&#x2F;swift-3-0-release-process&#x2F;</a>