Session End Event
There should be an "Event End" which is generated by the server when the Session expires.
This would allow to analyse the value of variables which are counted through a session.
Just one example, but we already have some use cases: We count the numbers of purchases within a session. If we use the purchase event we would get the session counted for all lower numbers of purchases as well.
ie. we have three purchases -> on usage of the purchase event (or any other event) we would get 1, 2 and 3 as attributed values. If we have a session end event we woudl count to 3 and would only get 3 for that event and evar combination.