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

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

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

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