public async void DownloadBook(bool fullBook)
        {
            _busyOverlay.Closable = true;
            _busyOverlay.Closing += GoBack;
            await _busyOverlay.Start(false);

            IsBusy = true;

            if (!_downloadController.DownloadBook(CatalogBookItemModel, CatalogId, fullBook))
            {
                _busyOverlay.Stop();
                _busyOverlay.Closing -= GoBack;
            }
        }
 private void Cancel()
 {
     SharingDataModel.Cancel();
     _busyOverlay.Closing -= Cancel;
     _busyOverlay.Stop();
 }