presto-orc/src/main/java/io/prestosql/orc/stream/LongOutputStreamV2.java/LongOutputStreamV2/recordCheckpoint
class LongOutputStreamV2:    @Override
    public void recordCheckpoint()
    {
        checkState(!closed);
        checkpoints.add(new LongStreamV2Checkpoint(numLiterals, buffer.getCheckpoint()));
    }