Realm iv_table Structure in encrypted realm file


now i have been analyzing realm source code and fine some strange thing.
in source code, they save IV, hash of encrypted data, previous IV, has of previous encrypted data. but i thought it is ridiculous. when i decrypt a realm file, i just use IV(not previous IV). thus i guess if save previous IV in encrypted data then the size of realm file will be bigger and not use in mobile phone.

so my question is this

is there special reason for saving previous IV, and previous encrypted data??

if no reason, then plz modify that. i don’t want my file to be heavier