Javadoc
This LoginAttribute identifies a time after which any session associated
with this login should terminate. It is left unspecified whether or not
on-going user-triggered activity should terminate when the session is
terminated. It is also left unspecified how quickly a session should
terminate once the expiry time has elapsed. A time unlimited login with no
automatic time-based expiry is represented with the absence of this
LoginAttribute. It is legitimate for a LoginReply to have multiple Expire
LoginAttributes; the Expiry with the earliest getExpiry response wins.