More information for CPU and memory usage optimization please.

[28development]

Hi,

I recently saw that the new 4 Version has improved CPU and memory usage,
I did not update to V4 yet or used it so I can't tell for sure if it is noticeable.
I would like to know how much it improved the usage (Desktop & Mobile).

Unfortunately, the release notes only say the following:

[v4.0.189](https://github.com/mozilla/pdf.js/releases/tag/v4.0.189)
PDF.js 4.0 is a major release that contains a number of API changes, features and bugfixes. 
The following changes are highlighted:

...
Optimizations for CPU and memory usage
...

In the past, I had issues rendering larger PDF files using pdfjs, the PDF files had images as well, and I had to do manual workarounds, like loading pages individually, so I am curious about how the improvements have been made and if the improvements are noticeable. I especially had problems on mobile devices, which led to a crash of the webapplication.