Create client.dat.bak.
Add fullyResumed() to tell ClientLayerPersister whether we resumed fully or just restarted.
Refactor load() prior to implementing backup-reading support
Handle the salt through loaded too.
Don't write salt twice, once checksummed and once not. Ooops!
Move filename check outside.
Load from the backup if necessary and if it exists.
More robust, and add logging.
Doh!
Clarify, encapsulate.
Logging