You don’t need to do anything fancy on the server side, because byte range requests are automatically handled by HTTP 1.1 (https://en.wikipedia.org/wiki/Byte_serving).
Simply storing XOD to a web server (or S3 backet) is all that is requred, but sometimes you may need to adjust your server settings (e.g. https://groups.google.com/d/msg/pdfnet-webviewer/WM-xaUxuuPA/iLyjkTaTNoQJ, https://groups.google.com/d/msg/pdfnet-webviewer/vKFkyNHfJzU/VzTFZW9KMBcJ, https://groups.google.com/d/msg/pdfnet-webviewer/7KuMCdqE73g/38BogxYY0SUJ).
You can find more specific info about the WebViewer, XOD, and configuration issues in WebViewer forum/KB:
https://groups.google.com/forum/#!forum/pdfnet-webviewer