static <K, V extends @Nullable Object> Set<Entry<K, V>> transformEntries(
        Set<Entry<K, V>> entries) {
      return new ForwardingSet<Map.Entry<K, V>>() {
        @Override
        protected Set<Entry<K, V>> delegate() {
          return entries;
        }

        @Override
        public Iterator<Entry<K, V>> iterator() {
          return UnmodifiableEntry.transformEntries(super.iterator());
        }

    static <K, V extends @Nullable Object> Set<Entry<K, V>> transformEntries(
        Set<Entry<K, V>> entries) {
      return new ForwardingSet<Map.Entry<K, V>>() {
        @Override
        protected Set<Entry<K, V>> delegate() {
          return entries;
        }

        @Override
        public Iterator<Entry<K, V>> iterator() {
          return UnmodifiableEntry.transformEntries(super.iterator());
        }