code: func NewProductBuilder(name string, client speed.Client) *ProductBuilder {
  	completed, err := speed.NewPCPCounter(0, "products."+name+".count")
  	if err != nil {
  		log.Fatal("Could not create completed, error: ", err)
  	}
  
  	totalTime, err := speed.NewPCPGauge(0, "products."+name+".time")
  	if err != nil {
  		log.Fatal("Could not create totalTime, error: ", err)
  	}
  
  	client.MustRegister(completed)
  	client.MustRegister(totalTime)
  
  	return &ProductBuilder{
  		name:      name,
  		bound:     500,
  		completed: completed,
  		totalTime: totalTime,
  	}
  }
docs: // NewProductBuilder creates a new instance of ProductBuilder