This function is used to set the name of the session variable used to store the user's authentication details. The default for the session variable name is _authsession.
This function can not be called statically.
You have to use setSessionName(), if you are running two or more different applications with Auth on the same domain. If you don't use this function, a user who has once logged in at one of the applications can also use the other applications without logging in again!