public function getHeaders()
    {
        $headers = $this->header;
        $headers[] = 'User-Agent: ' . $this->getUserAgent();
        $itemId = $this->indexQueueItem->getIndexQueueUid();
        $pageId = $this->indexQueueItem->getRecordPageId();

        $indexerRequestData = [
            'requestId' => $this->requestId,
            'item' => $itemId,
            'page' => $pageId,
            'actions' => implode(',', $this->actions),
            'hash' => md5(
                $itemId . '|' .
                $pageId . '|' .
                $GLOBALS['TYPO3_CONF_VARS']['SYS']['encryptionKey']
            )
        ];

        $indexerRequestData = array_merge($indexerRequestData, $this->parameters);
        $headers[] = 'X-Tx-Solr-Iq: ' . json_encode($indexerRequestData, JSON_HEX_TAG | JSON_HEX_APOS | JSON_HEX_AMP | JSON_HEX_QUOT | JSON_UNESCAPED_SLASHES);

        return $headers;
    }