C#和php都有sleep让线程休眠指定时间后再继续执行后面的代码，swift中应该如何呢？
首先，找一下objective-c版本是怎么做的

[self performSelector:@selector(didTimeOut:) withObject:nil afterDelay:60];// 顺便演示下取消[NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(didTimeout：) object:nil]

经过查找，swift中可以这么做：

var timer = NSTimer.scheduledTimerWithTimeInterval(0.1, target: self, selector: Selector("someSelector"), userInfo: nil, repeats: false)func someSelector() {    // Something after a delay}

或者这样：

var delta: Int64 = 1 * Int64(NSEC_PER_SEC)var time = dispatch_time(DISPATCH_TIME_NOW, delta)dispatch_after(time, dispatch_get_main_queue(), {    println("closures are " + txt)    resolve()});// 当然没这么恐怖，time可以直接传数字时间dispatch_after(1, dispatch_get_main_queue(), {    // your function here})

按C#的Threading.Thread.sleep(5000)的写法，swift中有：

NSThread.sleepForTimeInterval(3)

可实际上，一个跟php完全一样的用法是完全可行的：

sleep(3)