@Override
    public Iterator<CharSequence> iterator() {
        return Iterators.transform(wrapperSet.iterator(), CharSequenceWrapper::get);
    }
Copied from iceberg 1.1.x. Modify Set to concurrent Set.
inlong-sort/sort-flink/sort-flink-v1.13/sort-connectors/iceberg/src/main/java/org/apache/inlong/sort/iceberg/sink/trick/CharSequenceSet.java