Microsoft.R.Host.Client.DataTransferSession.FetchFileAsync C# (CSharp) Method

        public async Task FetchFileAsync(IRBlobInfo blob, string filePath, bool doCleanUp, IProgress<long> progress, CancellationToken cancellationToken) {
            using (RBlobStream blobStream = await RBlobStream.OpenAsync(blob, _blobService))
            using (Stream fileStream = _fs.CreateFile(filePath)) {
                await blobStream.CopyToAsync(fileStream, progress, cancellationToken);
            }

            if (doCleanUp) {
                _cleanup.Add(blob);
            }
        }

 private async Task RMarkdownRenderAsync(IRSession session, IFileSystem fs, string inputFilePath, string outputFilePath, string format, int codePage, IApplicationShell appShell) {
     using (var fts = new DataTransferSession(session, fs)) {
         string currentStatusText = string.Empty;
         uint cookie = 0;
         IVsStatusbar statusBar = null;
         appShell.DispatchOnUIThread(() => {
             statusBar = appShell.GetGlobalService<IVsStatusbar>(typeof(SVsStatusbar));
             statusBar.GetText(out currentStatusText);
             statusBar.Progress(ref cookie, 1, "", 0, 0);
         });
         
         try {
             // TODO: progress and cancellation handling
             appShell.DispatchOnUIThread(() => { statusBar?.Progress(ref cookie, 1, Resources.Info_MarkdownSendingInputFile.FormatInvariant(Path.GetFileName(inputFilePath)), 0, 3); });
             var rmd = await fts.SendFileAsync(inputFilePath, true, null, CancellationToken.None);
             appShell.DispatchOnUIThread(() => { statusBar?.Progress(ref cookie, 1, Resources.Info_MarkdownPublishingFile.FormatInvariant(Path.GetFileName(inputFilePath)), 1, 3); });
             var publishResult = await session.EvaluateAsync<ulong>($"rtvs:::rmarkdown_publish(blob_id = {rmd.Id}, output_format = {format.ToRStringLiteral()}, encoding = 'cp{codePage}')", REvaluationKind.Normal);
             appShell.DispatchOnUIThread(() => { statusBar?.Progress(ref cookie, 1, Resources.Info_MarkdownGetOutputFile.FormatInvariant(Path.GetFileName(outputFilePath)), 2, 3); });
             await fts.FetchFileAsync(new RBlobInfo(publishResult), outputFilePath, true, null, CancellationToken.None);
             appShell.DispatchOnUIThread(() => { statusBar?.Progress(ref cookie, 1, Resources.Info_MarkdownPublishComplete.FormatInvariant(Path.GetFileName(outputFilePath)), 3, 3); });
         } finally {
             appShell.DispatchOnUIThread(() => {
                 statusBar?.Progress(ref cookie, 0, "", 0, 0);
                 statusBar?.SetText(currentStatusText);
             });
         }
     }
 }