presto-orc/src/main/java/io/prestosql/orc/metadata/OrcMetadataReader.java/OrcMetadataReader/readPostScript
class OrcMetadataReader:    @Override
    public PostScript readPostScript(InputStream inputStream)
            throws IOException
    {
        CodedInputStream input = CodedInputStream.newInstance(inputStream);
        OrcProto.PostScript postScript = OrcProto.PostScript.parseFrom(input);

        return new PostScript(
                postScript.getVersionList(),
                postScript.getFooterLength(),
                postScript.getMetadataLength(),
                toCompression(postScript.getCompression()),
                postScript.getCompressionBlockSize(),
                toHiveWriterVersion(postScript.getWriterVersion()));
    }