     var val: Int32 = 0
 
     for (var i = 0; i < 100; ++i) {
-      queue.queueBlock({ OSAtomicIncrement32(&val); return })
+      queue.queueBlock({ OSAtomicIncrement32(&val) })
     }
     queue.queueAndAwaitBarrierBlock({})
     XCTAssertEqual(val, 100)

    var barrierVal: Int32 = 0

    for (var i = 0; i < 100; ++i) {
      queue.queueBlock({ OSAtomicIncrement32(&val); return })
    }
    queue.queueBarrierBlock({
      barrierVal = val
      semaphore.signal()
    })
    for (var i = 0; i < 100; ++i) {
      queue.queueBlock({ OSAtomicIncrement32(&val); return })
    }

    semaphore.wait()

    XCTAssertEqual(val, 1)
    
    let now = NSDate()
    XCTAssertTrue(now.timeIntervalSinceDate(then) > 0.4 && now.timeIntervalSinceDate(then) < 0.6)
  }
  
  func testQueueAndAwaitBlock() {
