how to use upsert ? can you give a example? about go-elasticsearch HOT 1 CLOSED

//+build ignore

package main

import (
	"log"
	"strings"

	"github.com/elastic/go-elasticsearch/v8"
)

func main() {
	log.SetFlags(0)

	es, err := elasticsearch.NewDefaultClient()
	if err != nil {
		log.Fatalf("Error creating the client: %s", err)
	}

	res, err := es.Update(
		"test",
		"1",
		strings.NewReader(`{
      "script" : {
        "source": "ctx._source.counter += params.count",
        "lang": "painless",
        "params" : {
            "count" : 4
        }
      },
      "upsert" : {
        "counter" : 1
      }
    }`),
	)

	log.Println(res.Status(), err)

	log.Println(es.Get("test", "1"))
}