GCD 延时方法 (Swift)

func delay(delay:Double, closure:()->()) {
    dispatch_after(
        dispatch_time(
            DISPATCH_TIME_NOW,
            Int64(delay * Double(NSEC_PER_SEC))
        ),
        dispatch_get_main_queue(), closure)
}


//And now you can talk like this:
delay(0.4) {
    // do stuff
}