@Override
        public Uuid next() {
            if (!hasNext()) throw new NoSuchElementException();
            Uuid result = next;
            next = null;
            return result;
        }
TopicIds is initialized with topic names (String) but exposes a Set of topic ids (Uuid) to the
user and performs the conversion lazily with TopicsImage.
group-coordinator/src/main/java/org/apache/kafka/coordinator/group/modern/TopicIds.java