Hi elasticsearch resthighlevelclient SocketTimeOutException issue

[slowup (nic k)]

As the title says, I'm currently facing a SocketTimeoutException.
There are almost no servers and it happens even expected (about 2 per traffic?)

So I think it's a client problem, not a server performance problem.
It mainly comes in color...
Client, es server version is 6.8
refresh interval 1s

RestHighLevelClient(
            RestClient
                .builder(HttpHost.create(properties.uri))
                .apply {
                    setHttpClientConfigCallback {
                        it.setDefaultCredentialsProvider(getCredential())
                    }
                    setRequestConfigCallback {
                        it.setSocketTimeout(3000)
                        it.setConnectTimeout(3000)
                    }
                }
        )


val request = UpdateRequest(indexName, INDEX_TYPE, id)
                .doc(JsonObjectUtil.toMap(entity))
                .upsert(
                    IndexRequest(indexName)
                        .type(INDEX_TYPE)
                        .id(id)
                        .source(JsonObjectUtil.toMap(entity))
                )
                .retryOnConflict(retryOnConflictCount)
                .setRefreshPolicy(WriteRequest.RefreshPolicy.WAIT_UNTIL)
                .detectNoop(false)

            val response = client.update(
                request,
                RequestOptions.DEFAULT
            )