public static void WriteDialogNode(DialogNode dialog)
        {
            IFormatter formatter = new BinaryFormatter();
            Stream     stream    = new FileStream(sender_psid + "_dialog_content.txt", FileMode.Create, FileAccess.Write, FileShare.None);

            formatter.Serialize(stream, dialog);
            stream.Close();
        }
 protected void EndDialog(DialogNode dialog_node)
 {
     Program.WriteDialogNode(dialog_node); Environment.Exit(0);
 }