presto-orc/src/main/java/io/prestosql/orc/metadata/OrcMetadataReader.java/OrcMetadataReader/readRowIndexes
class OrcMetadataReader:    @Override
    public List<RowGroupIndex> readRowIndexes(HiveWriterVersion hiveWriterVersion, InputStream inputStream)
            throws IOException
    {
        CodedInputStream input = CodedInputStream.newInstance(inputStream);
        OrcProto.RowIndex rowIndex = OrcProto.RowIndex.parseFrom(input);
        return rowIndex.getEntryList().stream()
                .map(rowIndexEntry -> toRowGroupIndex(hiveWriterVersion, rowIndexEntry))
                .collect(toImmutableList());
    }