code: protected function getContainerBuilder(): PluginContainerBuilder
      {
          $container = new PluginContainerBuilder($this->getPluginLoader(), []);
          $container->getParameterBag()->add($this->getKernelParameters());
  
          if (class_exists(Configuration::class) && class_exists(RuntimeInstantiator::class)) {
              $container->setProxyInstantiator(new RuntimeInstantiator());
          }
  
          return $container;
      }
docs: {@inheritdoc}