[RFC][DISCUSSION] Add clean and complete session save handler interface

Hi all, I about to write new RFC, but I would like to start discuss first. I sent PR that adds clean and complete session save handler interface. Older session save handler object/interfaces may be kept, but they should be deprecated because they are obsolete. There is no point making users to use them as recommended API. https://github.com/php/php-src/pull/2234 Please refer to PR for details. BTW, users will lose ability to modify session data with recommended API, requires to use obsolete API and dirty/inefficient hack to use user's own serialization if "User defined session serializer RFC" don't pass. https://wiki.php.net/rfc/user_defined_session_serializer If you would like to avoid this, please support the RFC. Thank you. Regards,