presto-main/src/main/java/io/prestosql/operator/unnest/UnnestOperator.java/UnnestOperator/getCurrentMaxEntries
class UnnestOperator:    private int getCurrentMaxEntries()
    {
        return unnesters.stream()
                .mapToInt(Unnester::getCurrentUnnestedLength)
                .max()
                .orElse(0);
    }