/**
  * Returns the builder assigned to this display variant.
  *
  * @return \Drupal\panels\Plugin\DisplayBuilder\DisplayBuilderInterface
  *   A display builder plugin instance.
  */
 public function getBuilder()
 {
     if (!isset($this->builder)) {
         $this->builder = $this->builderManager->createInstance($this->configuration['builder'], []);
     }
     return $this->builder;
 }