code: func QueryInstant(url, query string, p printer) int {
  	config := api.Config{
  		Address: url,
  	}
  
  	// Create new client.
  	c, err := api.NewClient(config)
  	if err != nil {
  		fmt.Fprintln(os.Stderr, "error creating API client:", err)
  		return 1
  	}
  
  	// Run query against client.
  	api := v1.NewAPI(c)
  
  	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Minute)
  	val, err := api.Query(ctx, query, time.Now())
  	cancel()
  	if err != nil {
  		fmt.Fprintln(os.Stderr, "query error:", err)
  		return 1
  	}
  
  	p.printValue(val)
  
  	return 0
  }
docs: // QueryInstant performs an instant query against a Prometheus server.