tests/sav/custom_serialization.res

   1 {"id":"a","semi_private":"secret","i":1}
   2 {"id":"a","semi_private":,"i":1,"more-data":"So Much Fun"}
   3 {"id":"b","semi_private":"secret","a":{"id":"a","semi_private":"secret","i":1}}
   4 {"id":"b","semi_private":,"a":,"a":"ID:a","more-data":"So Much Fun"}