onLoadProgress total is NaN when fetching a pdf from a url

[shihabdider]

Before you start - checklist

• I followed instructions in documentation written for my React-PDF version
• I have checked if this bug is not already reported
• I have checked if an issue is not listed in Known issues
• If I have a problem with PDF rendering, I checked if my PDF renders properly in PDF.js demo

Description

I am trying to create a progress bar which displays while the pdf is loading. When fetching a large pdf from a url, the total attribute of the onLoadProgress callback is NaN until the very end, when the pdf is fully loaded (which defeats the purpose of a loading bar).

I suspect this is not really a bug, but I'm wondering how/whether it's possible to get the total by some other means. Otherwise, I can just use a spinning wheel, but the progress bar is obviously better.

Steps to reproduce

Try to load a large pdf by supplying its url to the file prop. Then log the onLoadProgress callback's total attribute.

Expected behavior

Ideally it should compute the total for the fetched document somehow (perhaps using the headers?)

Actual behavior

It set as NaN until the very end. loaded works just fine.

Additional information

No response

Environment

• Browser (if applicable):
• React-PDF version:
• React version:
• Webpack version (if applicable):