为什么这段代码执行速度比预期的要快？

I have this code:

我有这个代码:

    public void replay() {
        long previous = DateTime.Now.Ticks;
        for (int i = 0; i < 1000; i++) {
            Thread.Sleep(300);
            long cur = DateTime.Now.Ticks;
            Console.WriteLine(cur - previous);
            previous = cur;
        }
    }
    public void r