代码：

CancellationTokenSource cancelSource = new CancellationTokenSource();
            cancelSource.Token.Register(() =>
            {
                Console.WriteLine(">>This is CancellationToken msg: task is canceled");
            });
            Task t = new Task(() =>
            {
                for (int i = 0; i < 10; i++)
                {
                    if (cancelSource.IsCancellationRequested)
                    {
                        Console.WriteLine(">>cancellationTokenSource cancel the task");
                        cancelSource.Token.ThrowIfCancellationRequested();
                        break;
                    }
                    Thread.Sleep(200);
                    Console.WriteLine("first:{0}", i);
                    //throw new Exception("Error");
                }
            }, cancelSource.Token);

这个cancelSource.Token在任务中怎么使用，或者是由谁来使用的，设置或不设置这个参数会有什么影响