presto-main/src/main/java/io/prestosql/operator/aggregation/IntervalDayToSecondAverageAggregation.java/IntervalDayToSecondAverageAggregation/combine
class IntervalDayToSecondAverageAggregation:    @CombineFunction
    public static void combine(LongAndDoubleState state, LongAndDoubleState otherState)
    {
        state.setLong(state.getLong() + otherState.getLong());
        state.setDouble(state.getDouble() + otherState.getDouble());
    }