public static UnboundLongFlag defineLongFlag(String flagId, long defaultValue, List<String> owners,
                                                 String createdAt, String expiresAt, String description,
                                                 String modificationEffect, Dimension... dimensions) {
        return define(UnboundLongFlag::new, flagId, defaultValue, owners, createdAt, expiresAt, description, modificationEffect, dimensions);
    }
WARNING: public for testing: All flags should be defined in {@link Flags}.
flags/src/main/java/com/yahoo/vespa/flags/Flags.java