:class:`Symfony\\Component\\HttpFoundation\\Session\\Storage\\Handler\\SessionHandlerProxy`

will be used to wrap any custom save handlers, that implement:phpclass:`SessionHandlerInterface`.

Under PHP 5.4 and above, all session handlers implement:phpclass:`SessionHandlerInterface`

From PHP 5.4 and above, all session handlers implement:phpclass:`SessionHandlerInterface`

including `Native*SessionHandler` classes which inherit from:phpclass:`SessionHandler`.

The proxy mechanism allows you to get more deeply involved in session save handler

classes. A proxy for example could be used to encrypt any session transaction

without knowledge of the specific save handler.

..note::

Before PHP 5.4, you can only proxy user-land save handlers but not

native PHP save handlers.

.. _`php.net/session.customhandler`:http://php.net/session.customhandler

.. _`php.net/session.configuration`:http://php.net/session.configuration