presto-main/src/main/java/io/prestosql/operator/aggregation/state/DigestAndPercentileArrayStateFactory.java/DigestAndPercentileArrayStateFactory/createSingleState
class DigestAndPercentileArrayStateFactory:    @Override
    public DigestAndPercentileArrayState createSingleState()
    {
        return new SingleDigestAndPercentileArrayState();
    }