How to get response from Serial Differencing Aggregation in java client

My aggregation code is as below, so what will be the aggregation response code?

RestHighLevelClient hclient = client.getClient();

SearchResponse response = hclient.search(new SearchRequest(index)
                    .source(
                            new SearchSourceBuilder()
    .query(new QueryBuilders.boolQuery().must(QueryBuilders.rangeQuery("@timestamp").from("now-12d").to("now")))

            .aggregation(
                    AggregationBuilders.dateHistogram("mainAgg")
                                        .field("@timestamp")
                                        .dateHistogramInterval(new DateHistogramInterval("1d"))
                                        .subAggregation(AggregationBuilders.count("subAgg")
                                                .field("host.name")
                                        )
                                        .subAggregation(PipelineAggregatorBuilders.diff("diffAgg","subAgg")
                                                .lag(1)
                                        )
                        )
                .size(0)
            ), RequestOptions.DEFAULT);

    Aggregations agg = response.getAggregations();
    Histogram subterm = agg.get("mainAgg");

    for (Histogram.Bucket subEntry : subTerm.getBuckets()) {

    ValueCount count = subEntry.getAggregations().get("subAgg2");

    HOW to get Pipeline aggregation result here ??????

    }

    hclient.close();

How to get pipeline aggregation to result in for loop?

please help

Anybody please reply

How to get responds from Serial Differencing Aggregation in java high level client Elasticsearch