presto-main/src/main/java/io/prestosql/operator/aggregation/arrayagg/ArrayAggregationStateFactory.java/ArrayAggregationStateFactory/getSingleStateClass
class ArrayAggregationStateFactory:    @Override
    public Class<? extends ArrayAggregationState> getSingleStateClass()
    {
        return SingleArrayAggregationState.class;
    }