It is the only mode that supports the Session_OnEnd event that we used previously.
Timeout value (in minutes, not in seconds) configures how long our sessions are kept 'alive' - in other words
here we set how long our users can be inactive before considered Offline.
In this example timeout is set to 20 minutes, so while our visitors click on some links in our website at least once
in a 20 minutes, they are considered online.