presto-hive/src/main/java/io/prestosql/plugin/hive/parquet/HdfsParquetDataSource.java/ReferenceCountedReader/read
class ReferenceCountedReader:        @Override
        public Slice read()
        {
            checkState(referenceCount > 0, "Chunk reader is already closed");

            if (data == null) {
                byte[] buffer = new byte[range.getLength()];
                readFully(range.getOffset(), buffer, 0, buffer.length);
                data = Slices.wrappedBuffer(buffer);
            }

            return data;
        }