Add `on_commit_callback` to put the responsibility of renaming the directories on the users of the serialization library. This will also fix the GCS atomic rename issue where the users can write a success file when the commit is successful and check the existence of that file before deserialization.
Add `on_commit_callback` to put the responsibility of renaming the directories on the users of the serialization library. This will also fix the GCS atomic rename issue where the users can write a success file when the commit is successful and check the existence of that file before deserialization.

PiperOrigin-RevId: 463238200

google/paxml,google/paxml