How to delay response to user text entry until after user finishes typing

delayed_text_entry

// http://forums.xamarin.com/discussion/comment/133731/#Comment_133731

public partial class Page1
{
    public Page1()
    {
        this.InitializeComponent();
        this.Entry.TextChanged += this.EntryOnTextChanged;
    }
    //
    private CancellationTokenSource throttleCts = new CancellationTokenSource();
    private void EntryOnTextChanged(object sender, TextChangedEventArgs args)
    {
        Interlocked.Exchange(ref this.throttleCts, new CancellationTokenSource()).Cancel();
        Task.Delay(TimeSpan.FromMilliseconds(500), this.throttleCts.Token) // throttle time
            .ContinueWith(
                delegate { this.HandleString(this.Entry.Text); },
                CancellationToken.None,
                TaskContinuationOptions.OnlyOnRanToCompletion,
                TaskScheduler.FromCurrentSynchronizationContext());
    }
    //
    private void HandleString(string str)
    {
        // .. if CanExecute(...) Execute(...)
        this.Label.Text = str.Length.ToString();
    }
}