Executes the block after a delay of x seconds.

ExecuteAfter.swift

//Swfit 2
func delay(seconds seconds: Double, completionBlock: () -> ()) {
    let delay = seconds * Double(NSEC_PER_SEC)
    let time = dispatch_time(DISPATCH_TIME_NOW, Int64(delay))
    dispatch_after(time, dispatch_get_main_queue()) {
        completionBlock()
    }
}

//Swift 3
func delay(seconds: Double, completionBlock: @escaping () -> ()) {
    DispatchQueue.main.asyncAfter(deadline: .now() + seconds) {
        completionBlock()
    }
}

delay(seconds: 2, completionBlock: { print("completed") })
delay(seconds: 2) {
    print("completed")
}