Thanks for providing the required information.
You are getting the exception because the stream object doesn’t contain any data for the blank document and the length of the stream is 0 in that case. However, the exception is not thrown when rendering document using the file name. To tackle this situation, you can use following code.
var container = _viewerImageHandler.GetPdfFile(fileStream, new PdfFileOptions());
We are unable to reproduce this issue at our end and the document is getting rendered within a few seconds. Would you please share with us the complete source code you are using to render the document?
We have successfully reproduced this issue at our end. The issue has been logged in our issue tracking system (with ID: VIEWERNET-1414) for further investigation. In case of any further updates, we will keep you informed.