presto-orc/src/main/java/io/prestosql/orc/metadata/CompressedMetadataWriter.java/CompressedMetadataWriter/writePostscript
class CompressedMetadataWriter:    public Slice writePostscript(int footerLength, int metadataLength, CompressionKind compression, int compressionBlockSize)
            throws IOException
    {
        // postscript is not compressed
        DynamicSliceOutput output = new DynamicSliceOutput(64);
        metadataWriter.writePostscript(output, footerLength, metadataLength, compression, compressionBlockSize);
        return output.slice();
    }