code: public function init()
      {
          parent::init();
  
          $this->cache = $this->enabled ? Instance::ensure($this->cache, 'yii\caching\CacheInterface') : null;
  
          if ($this->cache instanceof CacheInterface && $this->getCachedContent() === false) {
              $this->getView()->pushDynamicContent($this);
              ob_start();
              ob_implicit_flush(false);
          }
      }
docs: Initializes the FragmentCache object.