Initial high CPU load on Firefox

[boardend]

When Firefox is loading the qgis-js WebAssembly module, one core is 100% busy for some time. This is likely something FF does internally when loading such a large .wasm module:

• The high CPU load goes towards zero after some time (~4min on my machine). The website is still working/responsive after that and stays idle when doing more render calls
• The same thing happens with the 0.0.3 version, see https://boardend.github.io/qgis-js-baseline/
• The same thing happens if I just return 0 in the main function
• This behavior was observed in FF on Ubuntu Wayland and X11, also on FF on Windows 11
• FF profiler only shows that the PollWrapper is busy polling
• Hard to judge, but it seems that other larger Qt projects show similar behavior, although not as extreme as in qgis-js:
  • https://ripes.me/ (32MB)
  • https://fwcd.dev/m1xxx/ (304MB)