EAuthServiceBase::setState PHP Method

    protected function setState($key, $value, $defaultValue = null)
    {
        $session = Yii::app()->session;
        $key = $this->getStateKeyPrefix() . $key;
        if ($value === $defaultValue) {
            unset($session[$key]);
        } else {
            $session[$key] = $value;
        }
    }