/** The key of the configuration. e.g. label */
    String QUERY_FACET_FIELDS = "query.facet.fields";

    /** The key of the configuration. e.g. 100 */
    String QUERY_FACET_FIELDS_SIZE = "query.facet.fields.size";

    /** The key of the configuration. e.g. 1 */
    String QUERY_FACET_FIELDS_min_doc_count = "query.facet.fields.min_doc_count";

    /** The key of the configuration. e.g. count.desc */