CancellationTokenSource cancelTokenSource = new CancellationTokenSource();

                Task.Run(() =>
                {
                    while (!cancelTokenSource.IsCancellationRequested)
                    {
                        Console.WriteLine(DateTime.Now);
                        Thread.Sleep(5000);
                    }
                }, cancelTokenSource.Token);

                Console.WriteLine("按任務(wu)鍵取消(xiao)這個任務(wu)");
                Console.ReadLine();

                cancelTokenSource.Cancel();

                Console.WriteLine("已停止");
                Console.ReadLine();