presto-main/src/main/java/io/prestosql/sql/planner/iterative/rule/PruneAggregationSourceColumns.java/PruneAggregationSourceColumns/getAggregationInputs
class PruneAggregationSourceColumns:    private static Stream<Symbol> getAggregationInputs(AggregationNode.Aggregation aggregation)
    {
        return Streams.concat(
                SymbolsExtractor.extractUnique(aggregation).stream(),
                aggregation.getMask().map(Stream::of).orElse(Stream.empty()));
    }