presto-orc/src/main/java/io/prestosql/orc/stream/UncompressedOrcChunkLoader.java/UncompressedOrcChunkLoader/nextChunk
class UncompressedOrcChunkLoader:    @Override
    public Slice nextChunk()
            throws IOException
    {
        if (nextPosition >= dataReader.getSize()) {
            throw new OrcCorruptionException(dataReader.getOrcDataSourceId(), "Read past end of stream");
        }

        Slice chunk = dataReader.seekBuffer(nextPosition);
        dataReaderMemoryUsage.setBytes(dataReader.getRetainedSize());
        lastCheckpoint = createInputStreamCheckpoint(0, nextPosition);
        nextPosition += chunk.length();

        return chunk;
    }