public StatusChangedEventArgs(DownloadConnectionStatus oldStatus, DownloadConnectionStatus newStatus)
 {
     OldStatus = oldStatus;
     NewStatus = newStatus;
 }
 protected void OnStatusChanged(DownloadConnectionStatus oldStatus, DownloadConnectionStatus newStatus)
 {
     StatusChanged?.Invoke(this, new StatusChangedEventArgs(oldStatus, newStatus));
 }