How do i write csv file in loop

Question

below is my java client query in which im trying write my data in csv file i'm stuck on for loop not able to understand what should i parse in for loop can Below is my code

    public class ElasticQ {

    public static void main(String[] args) {
        RestClient restClient = RestClient.builder(
                new HttpHost("host", 1212, "http")
        ).build();

        ElasticsearchTransport transport = new RestClientTransport(
                restClient, new JacksonJsonpMapper());

        ElasticsearchClient client = new ElasticsearchClient(transport);


        try {
            var sub3TermAggregation = new Aggregation.Builder()
                    .sum(new SumAggregation.Builder()
                            .field("labels.row_count").build())
                    .build();

            var sub4Aggregation = new Aggregation.Builder()
                    .terms(new TermsAggregation.Builder()
                            .field("labels.job_id")
                            .size(100000)
                            //   .order(List.of("_key", SortOrder.Desc))
                            .minDocCount(1)
                            .build())
                    .aggregations("3", sub3TermAggregation)
                    .build();

            var aggregation = new Aggregation.Builder()
                    .terms(new TermsAggregation.Builder()
                            .field("labels.client_id")
                            .size(100000)
                            //     .order(List.of("_key", SortOrder.Desc))
                            .minDocCount(1)
                            .build())
                    .aggregations("4", sub4Aggregation)
                    .build();

            var boolquery = BoolQuery
                    .of(b -> b.filter(Query
                            .of(q -> q.range(RangeQuery
                                    .of(r -> r.field("@timestamp")
                                            .gte(JsonData.of("1664755200000"))
                                            .lte(JsonData.of("1664787600000"))
                                            .format("epoch_millis")
                                    ))
                            )).filter(f -> f.queryString(QueryStringQuery.of(qs -> qs
                            .query("service.name:*itm*").analyzeWildcard(true))))
                    );
            var query = Query.of(q -> q.bool(boolquery));

            var searchRequest = new SearchRequest.Builder()
                    .index("*itm*")
                    .size(0)
                    .query(query)
                    .aggregations("2", aggregation)
                    .build();

            var response = client.search(searchRequest, Void.class);    
            var aggs2 = response.aggregations().get("2");

            if (Objects.nonNull(aggs2)) {
                var buckets = aggs2.sterms().buckets().array();

                for (StringTermsBucket bucket : buckets) {
                    var subAggs4 = bucket.aggregations().get("4");



                    subAggs4.sterms().buckets().array().forEach(agg3Bucket -> {


                        try {
                            FileWriter fWriter = new FileWriter(
                                    "/home/rain/Downloads/ElasticNestedQuery-main/demo.csv");


                            for () {
                                System.out.println(bucket.key() + bucket.docCount() + ","
                                        + agg3Bucket.key() + agg3Bucket.docCount() + ","
                                        + agg3Bucket.aggregations().get("3").sum().value());

                            }

                            fWriter.close();
                        } catch (IOException e) {
                            throw new RuntimeException(e);
                        }

                        System.out.println(bucket.key() + bucket.docCount() + "," +
                                 agg3Bucket.key() + agg3Bucket.docCount() + ","  + agg3Bucket.aggregations().get("3").sum().value());
                    });
                }

            }

        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }
}

this is how my result of query look like

86206181,12157261,2.0 86206181,12157271,3318.0 86206181,12157301,3369.0 86206181,12157311,3376.0

now i just need to write it down in csv file can some one help me here