<Grid x:Name="LayoutRoot">
    <Grid.RowDefinitions>
        <RowDefinition Height="Auto" />
        <RowDefinition Height="*" />
    </Grid.RowDefinitions>
    <c1:C1TextBox x:Name="txtFilter" TextChanged="C1TextBox_TextChanged"  Placeholder="Type here to filter"  Grid.Row="0" Margin="10 0 0 10" Width="300" HorizontalAlignment="Left"/>
    <c1:C1ListView x:Name="listView" Grid.Row="1" DisplayMemberPath="Name" Margin="10 0 10 10" />
</Grid>

string currentFilterValue;
System.Threading.SemaphoreSlim filterSemaphore;
public MainWindow()
{
    InitializeComponent();
    //Bind to datasource
    filterSemaphore = new System.Threading.SemaphoreSlim(1);
    txtFilter.Text = "";
    listView.ItemsSource = Person.Generate(100);
}
// Add grouping by FilterAsync method
private async void C1TextBox_TextChanged(object sender, TextChangedEventArgs e)
{
    try
    {
        var filter = txtFilter.Text;
        currentFilterValue = filter;
        await Task.Delay(400);
        await filterSemaphore.WaitAsync();
        if (currentFilterValue == filter)
        {
            await listView.DataCollection.FilterAsync("Name", FilterOperation.Contains, filter);
        }
    }
    finally
    {
        filterSemaphore.Release();
    }
}