CancellationToken和Task的问题

var tokenSource = new CancellationTokenSource();

var token = tokenSource.Token;

Task.Run(() =>

{

    while (true)

    {

        token.ThrowIfCancellationRequested();

        Console.WriteLine($"[1] {DateTime.Now:mm:ss.fff}");

        Thread.Sleep(1000);

    }

}, token);

Task.Run(() =>

{

    Thread.Sleep(5000);

    Console.WriteLine($"[2] {DateTime.Now:mm:ss.fff}");

    tokenSource.Cancel();

});