code: public function consume(ItemPipelineEvent $event)
      {
          if (!$this->setItem($event)) {
              return;
          }
  
          $this->log(
              sprintf(
                  'Start update single document of type %s id: %s',
                  get_class($this->getItem()->getDocument()),
                  $this->getItem()->getDocument()->getId()
              )
          );
  
          if (!$this->persistDocument()) {
              return;
          };
  
          $this->log('End an update of a single document.');
      }
docs: Consume event.
  
  @param ItemPipelineEvent $event