public static void Show()
        {
            var sampleForeground = new ThreadSample(10);
            var sampleBackground = new ThreadSample(20);

            var threadOne = new Thread(sampleForeground.CountNumbers);

            threadOne.Name = "ForegroundThread";
            var threadTwo = new Thread(sampleBackground.CountNumbers);

            threadTwo.Name         = "BackgroundThread";
            threadTwo.IsBackground = true;


            threadOne.Start();
            threadTwo.Start();
            Console.ReadLine();            //只剩下后台程序则直接结束工作;可以不用等待完全输出,输入按键退出控制台
        }
        static void RunThreads()
        {
            var sample = new ThreadSample();

            var threadOne = new Thread(sample.CountNumbers);

            threadOne.Name = "ThreadOne";
            var threadTwo = new Thread(sample.CountNumbers);

            threadTwo.Name = "ThreadTwo";

            threadOne.Priority = System.Threading.ThreadPriority.Highest;
            threadTwo.Priority = System.Threading.ThreadPriority.Lowest;
            threadOne.Start();
            threadTwo.Start();

            Thread.Sleep(TimeSpan.FromSeconds(2));
            sample.Stop();
        }