The prepended uniqueId should use underscore character _ instead of #
Scenario:
I want to read some session data with javascript. I use php-unserialize module from npm. If I set a uniqueId of the session,the keys of the returned object are containing # caracter. So I am unable to read object data like object.key because the key has # and it's an invalid character: object.uniqueId#key. I don't consider this a bug, but it's something that I want your opinion about.
