int delay = 1;
var cancellationTokenSource = new CancellationTokenSource();
var token = cancellationTokenSource.Token;
var listener = Task.Factory.StartNew(() =>
{
while (true)
{
// poll source
Thread.Sleep(delay);
if (token.IsCancellationRequested)
break;
}
// cleanup, e.g. close connection
}, token, TaskCreationOptions.LongRunning, TaskScheduler.Default);