Inheritance: FirstFloor.ModernUI.Presentation.Displayable, IWithId
 private async Task MarkAsRead(PieceOfInformation value) {
     if (value == null) return;
     await Task.Delay(1000);
     if (value != Piece) return;
     if (Application.Current.MainWindow?.IsActive == true) {
         value.MarkAsRead();
     }
 }
 private void OnPieceChanged(PieceOfInformation newValue) {
     MarkAsRead(newValue).Forget();
 }