Progress bar for file download

I have been using a progress wheel for a visual cue while pdfs are being loaded into a WebHTMLViewer. If a file is forced to be down loaded to the hard drive the borwser displays a nice progress bar, but not when loading directly to the browser. I would like to use a progress bar while loading direct to the browser. To make that work, howeve, I’m thinking I’ve got to know how long the load will take. Is that even possible?

I do know how big the file is. If I could get how much was loaded as it went, that would work as well.