Large app.ron causes significant slowdown during shutdown

[jleibs]

Describe the bug
Rerun takes 2-3 seconds to shutdown at quit.

To Reproduce
Not clear how I got into this state, but the attached app.ron definitely creates the issue for me. This app.ron is currently about 7.2M
app.ron.zip

Update: you can reproduce the behavior by opening any view and then repeatedly clicking the "repopulate viewport" button. Seems proportional to the number of space-views created.

• For structure_from_motion/main.py (3 space views) the file only grows at 500 bytes / repopulate.
• For open_photogrammetry_format/main.py --no-frames (118 space views) the file grows at 10k bytes / repopulate.

Expected behavior
app.ron should stay a reasonable size and rerun should shutdown quickly.

Screenshots

Backtrace

Desktop (please complete the following information):

• OS: Ubuntu 22.10

Rerun version
main

[emilk]

I'll add some GC:ing to the next egui release

[teh-cmc]

Tangent question: where are these 3.8s going? It shouldn't take anywhere near that to write 7M of data to page cache? Is it the RON serializer?

[emilk]

Yeah, I think so. I should switch to bincode or msgpack.

[emilk]

Will be fixed by:

• Prune old egui memory data when reaching some limit emilk/egui#3299

[emilk]

Here is another fix:

• Speed up eframe state storage emilk/egui#3353