CancellationToken and Thread.Sleep

I have a task that, when some condition occur, sleeps for a few seconds.
Most of the time, the task does some heavy processing, so I can't use a thread timer.

The problem with the sleep is that, whenever I cancel the task using the CancellationToken(Source), I have to wait for the sleep to finish before the task finishes. The Thread.Sleep doesn't have any CancellationToken parameter.

while(token.IsCancellationRequested == false)
{
    // Initial processing
 
    if ( someCondition == true )
    {
        // Sleep for 5 seconds
        Thread.Sleep(5000);
    }
    
    // Continue processing
}

The solution is quite simple - use the cancellation token's wait handle:

while(token.IsCancellationRequested == false)
{
    // Initial processing
 
    if ( someCondition == true )
    {
        // Sleep for 5 seconds, but exit if token is cancelled
        var cancelled = token.WaitHandle.WaitOne(5000);
 
        if ( cancelled )
            break;
    }
    
    // Continue processing
}

The token's waithandle is signaled when you cancel its CancellationTokenSource. The WaitOne will return true because the Wait was signaled (read: cancelled) before the timeout occured.

Nice.