New Swift 3.0 Dispatch APIs

Dispatch.swift

import Foundation
import PlaygroundSupport

PlaygroundPage.current.needsIndefiniteExecution = true

// Do something on the main queue asynchronously
DispatchQueue.main.async {
  print("Update UI")
}

// Do something after 2 seocnds
let someQueue = DispatchQueue(label: "some.example.queue")
let delayTime = DispatchTime.now() + .seconds(2)
someQueue.after(when: delayTime) {
  print("Done")
}

// Perform a task concurrently for specified iterations
DispatchQueue.concurrentPerform(iterations: 3) {
  print("\($0) time")
}

// Do something synchronously
someQueue.sync { 
  print("Blocking")
}