GCD dispatch_resume test for Swift

SwiftLoopTest.playground

import Foundation
import XCPlayground
import Dispatch

class Looper {
  
  var loopQueue : dispatch_queue_t!
  var tickSource : dispatch_source_t!
  
  init() {
    loopQueue = dispatch_queue_create("com.alexeckermann.looper", nil)
    println("looper initd")
  }
  
  func loop() {
    
    println("loop called")
    
    tickSource = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, loopQueue)
    dispatch_source_set_timer(tickSource, dispatch_time(DISPATCH_TIME_NOW, 0), (200 * NSEC_PER_MSEC), (50 * NSEC_PER_MSEC))
    dispatch_source_set_event_handler(tickSource) { println("success!") } // Looking for this to print to the output
    dispatch_async(loopQueue, { println("queue works") })
    
    dispatch_resume(tickSource) // Comment this out if it raises an exception/
    
  }
  
}

var looper = Looper()
looper.loop()

XCPSetExecutionShouldContinueIndefinitely(continueIndefinitely: true)