setIndexer example

        $ids = $request->request->all('ids');

        if (empty($ids)) {
            throw new BadRequestHttpException('Parameter `ids` is no array or empty');
        }

        $skips = array_filter(explode(',', (string) $request->headers->get(PlatformRequest::HEADER_INDEXING_SKIP, '')));

        $message = new ProductIndexingMessage($ids, null);
        $message->setIndexer('product.indexer');
        $message->addSkip(...$skips);

        $this->messageBus->dispatch($message);

        return new JsonResponse(null, Response::HTTP_NO_CONTENT);
    }
}

public function update(EntityWrittenContainerEvent $event): ?EntityIndexingMessage
    {
        $ids = $event->getPrimaryKeys(ProductStreamDefinition::ENTITY_NAME);

        if (empty($ids)) {
            return null;
        }

        foreach ($ids as $id) {
            $message = new ProductStreamMappingIndexingMessage($id);
            $message->setIndexer($this->getName());
            $this->messageBus->dispatch($message);
        }

        return null;
    }

    /** * @param string[] $ids */
    public function updateProducts(array $ids, Context $context): void
    {
        

$message = new ProductIndexingMessage(array_values($updates), null, $event->getContext());
        $message->addSkip(self::INHERITANCE_UPDATER, self::STOCK_UPDATER);

        $delayed = \array_unique(\array_filter(\array_merge(
            $this->getParentIds($updates),
            $this->getChildrenIds($updates)
        )));

        foreach (\array_chunk($delayed, 50) as $chunk) {
            $child = new ProductIndexingMessage($chunk, null, $event->getContext());
            $child->setIndexer($this->getName());
            EntityIndexerRegistry::addSkips($child, $event->getContext());

            $this->messageBus->dispatch($child);
        }

        return $message;
    }

    public function getTotal(): int
    {
        return $this->getIterator(null)->fetchCount();
    }

            if (\count($only) > 0 && !\in_array($indexer->getName(), $only, true)) {
                continue;
            }

            $offset = null;

            $this->dispatcher->dispatch(new ProgressStartedEvent($indexer->getName(), $indexer->getTotal()));

            while ($message = $indexer->iterate($offset)) {
                $message->setIndexer($indexer->getName());
                $message->addSkip(...$skip);

                $this->sendOrHandle($message, $useQueue);

                $offset = $message->getOffset();

                try {
                    $count = \is_array($message->getData()) ? \count($message->getData()) : 1;
                    $this->dispatcher->dispatch(new ProgressAdvancedEvent($count));
                } catch (\Exception) {
                }
            }