public void DownloadProgressChangedHandler(object sender, EventArgs e)
 {
     if (DateTime.UtcNow > LastUpdateTime.AddSeconds(1))
     {
         CalcuclateDownloadSpeed();
         CalculateAverageRate();
         UpdateDownlpadDisplay();
         LastUpdateTime = DateTime.UtcNow;
     }
 }
 private void UpgradeProperties()
 {
     if (DateTime.Now > LastUpdateTime.AddSeconds(1))
     {
         OnPropertyChanged("SpeedString");
         OnPropertyChanged("TotalUsedTimeString");
         LastUpdateTime = DateTime.Now;
     }
     OnPropertyChanged("SizeString");
     OnPropertyChanged("Progress");
 }