yii\authclient\SessionStateStorage::init PHP Method

    public function init()
    {
        parent::init();
        if ($this->session === null) {
            if (Yii::$app->has('session')) {
                $this->session = Yii::$app->get('session');
            }
        } else {
            $this->session = Instance::ensure($this->session, Session::className());
        }
    }