@Override
    public R next() {
      if (!hasNext()) {
        throw new IllegalStateException("next() called on rocksDB with no more valid entries");
      }
      R val = SerializationUtil.kryoDeserialize(iterator.value());
      iterator.next();
      return val;
    }
{@link Iterator} wrapper for RocksDb Iterator {@link RocksIterator}.
amoro-format-iceberg/src/main/java/org/apache/amoro/utils/map/RocksDBBackend.java