Rack::Session::Abstract::Persisted deletes the :same_site option and saves it off as an instance variable, then applies it with optional call support.

If I have an instance of Rack::Session::Abstract::Persisted, I can't get the same_site value out of it.

My use-case: I'm migrating from one type of session cookie to another and I want to copy all the directives, but same_site is always nil. I'm left having to do other.instance_variable_get(:same_site), which is an bug waiting to happen.