CAS (or If-Match, If-None-Match) is something that is atomic but localized to a single key. You don’t have to provide any additional consistency guarantees beyo

CAS (or If-Match, If-None-Match) is something that is atomic but localized to a single key. You don’t have to provide any additional consistency guarantees beyond what S3 already provides. You are providing a couple new atomic operation with the same radius as existing operations—everything is already atomic on a single key, you’re just adding conditions to those operations.