presto-orc/src/main/java/io/prestosql/orc/stream/PresentOutputStream.java/PresentOutputStream/recordCheckpoint
class PresentOutputStream:    public void recordCheckpoint()
    {
        checkArgument(!closed);
        groupsCounts.add(currentGroupCount);
        currentGroupCount = 0;

        if (booleanOutputStream != null) {
            booleanOutputStream.recordCheckpoint();
        }
    }