What is the purpose of passing CancellationToken to Task.Factory.StartNew()

Question

In the following code a CancellationToken is passed to the .StartNew(,) method as the 2nd parameter, but is only usable by the Action via the closure in the lambda. So, what is the purpose of passing the token through the .StartNew(,) method's 2nd parameter?

var cts = new CancellationTokenSource();
var token = cts.Token;
Task.Factory.StartNew(() => 
{
    while (true)
    {
        // simulate doing something useful
        Thread.Sleep(100);
    }
}, token);

Answer 1

Actually, the purpose of the CancellationToken passed to Task.Run and Taskfactory.StartNew is to allow the task to differentiate being cancelled by an exception thrown from CancellationToken.ThrowIfCancellationRequested and failing because of any other exception.

That is, if the CancellationToken passed at start throws, the task's state is Cancelled while any other exception (even from another CancellationToken) will set it to Faulted.

Also, if the CancellationToken is cancelled before the task actually starts, it won't be started at all.