public void OnMessage(MessageEventArgs e)
 {
     if (MessageEvent != null)
         MessageEvent(this, e);
 }
 static void downloader_MessageEvent(object sender, MessageEventArgs e)
 {
     Console.WriteLine(e.Message);
 }
 public void OnErrorMessage(MessageEventArgs e)
 {
     if (ErrorEvent != null)
         ErrorEvent(this, e);
 }
 static void downloader_ErrorEvent(object sender, MessageEventArgs e)
 {
     ShowErrorMessage(e.Message);
 }