public static <T> List<T> add(List<T> list, Collection<T> values) {
        if (isImmutable(list)) {
            List<T> newList = new ArrayList<>(list.size() + values.size());
            newList.addAll(list);
            list = newList;
        }
        list.addAll(values);
        return list;
    }
Note that the method only checks the immutable classes used by Turms.
turms-server-common/src/main/java/im/turms/server/common/infra/collection/CollectionUtil.java