generateMessage example

// Determine recipients, and prepare headers         $this->recipients = implode(',', $mail->getRecipients());
        $this->_prepareHeaders($this->_getHeaders($boundary));

        // Create message body         // This is done so that the same Zend_Mail object can be used in         // multiple transports         $message = new Zend_Mime_Message();
        $message->setParts($this->_parts);
        $message->setMime($mime);
        $this->body = $message->generateMessage($this->EOL);

        // Send to transport!         $this->_sendMail();
    }
}

        if (!$this->helper->allowIndexing()) {
            return;
        }

        $alias = $this->helper->getIndexName($definition);

        if (!$this->client->indices()->existsAlias(['name' => $alias])) {
            $this->init();
        }

        $this->__invoke($this->generateMessage($definition, $ids));
    }

    /** * @param array<string> $ids */
    private function generateMessage(EntityDefinition $definition, array $ids): ElasticsearchIndexingMessage
    {
        $context = Context::createDefaultContext();

        $alias = $this->helper->getIndexName($definition);