public byte[] DownloadDiagram(string diagramNumber)
        {
            assertConnected();
            try
            {
                // prepare for download
                string downloadFileClaimToken = wsClient.QueueDiagramDownload(accessToken(), diagramNumber);
                if (downloadFileClaimToken == null)
                {
                    return(null);
                }

                // download all parts
                return(downloadFileIncrementally(downloadFileClaimToken));
            }
            catch (Exception ex)
            {
                throw TranslateException(ex);
            }
        }