[bsdetector]

They already have Google's Brotli imported, they'd only need a small tweak to also include the encoder. Or use Snappy which is also in the codebase already.

Add the code that's able to load compressed session backups and leave it in for a couple versions.

Once enough versions have passed enable the code that writes compressed session backups.

It's really not that hard to do unless you want to enable it now.