final protected function resetUserIdentity(AUser $user = null, $duration = null) {
        engine('resetUserIdentity', $user, $duration);
        return $this;
    }
final protected function resetUserIdentity(AUser $user = null, $duration = null) {
        engine('resetUserIdentity', $user, $duration);
        return $this;
    }
final protected function resetUserIdentity ( AUser $ user = null , $ duration = null ) { engine ( 'resetUserIdentity' , $ user , $ duration ) ; return $ this ; }
Resets the user identity to guest
@param AUser $user
@param int $duration Duration for which the identity should be valid
@return AController
Resets the user identity to guest