* @return The source map.
    */
    protected Map<String, Object> toSource(final SearchLogEvent searchLogEvent) {
        final Map<String, Object> source = toLowerHyphen(searchLogEvent.toSource());
        source.put("_id", searchLogEvent.getId());
        // source.put("version_no", searchLogEvent.getVersionNo());
        source.put("event_type", searchLogEvent.getEventType());
        return source;
    }

    /**

        try {
            zos.putNextEntry(entry);
            SearchEngineUtil.scroll(index, hit -> {
                final String data = "{\"index\":{\"_index\":\"" + index + "\",\"_id\":\"" + StringEscapeUtils.escapeJson(hit.getId())
                        + "\"}}\n" + hit.getSourceAsString() + "\n";
                try {
                    zos.write(data.getBytes(Constants.CHARSET_UTF_8));

index.field.expires=expires
# Field name for URL in the index.
index.field.url=url
# Field name for document ID in the index.
index.field.doc_id=doc_id
# Field name for internal ID in the index.
index.field.id=_id
# Field name for version in the index.
index.field.version=_version
# Field name for sequence number in the index.
index.field.seq_no=_seq_no
# Field name for primary term in the index.

    String INDEX_FIELD_URL = "index.field.url";

    /** The key of the configuration. e.g. doc_id */
    String INDEX_FIELD_doc_id = "index.field.doc_id";

    /** The key of the configuration. e.g. _id */
    String INDEX_FIELD_ID = "index.field.id";

    /** The key of the configuration. e.g. _version */
    String INDEX_FIELD_VERSION = "index.field.version";

    /** The key of the configuration. e.g. _seq_no */

                                            .setIndex(configIndex)
                                            .setId(result.get("index").get("_id"))
                                            .setSource(source, XContentType.JSON);
                                    builder.add(requestBuilder);
                                }
                            }