private void deleteWorker_DoWork(object sender, DoWorkEventArgs e)
        {
            DirectMessage deleteMe = e.Argument as DirectMessage;

            // call twitter api
            TwitterClient client = new TwitterClient(_username, _password);

            try
            {
                client.DestroyDirectMessage(deleteMe.Id);
                client.Close();
                e.Result = deleteMe;
            }
            finally
            {
                client.Abort();
            }
        }