presto-orc/src/main/java/io/prestosql/orc/OrcOutputBuffer.java/OrcOutputBuffer/getCheckpoint
class OrcOutputBuffer:    public long getCheckpoint()
    {
        if (compressor == null) {
            return size();
        }
        return InputStreamCheckpoint.createInputStreamCheckpoint(compressedOutputStream.size(), bufferPosition);
    }