code: func Add(m types.Metric) {
  	name := m.Info().Name
  
  	lock.Lock()
  	defer lock.Unlock()
  
  	if _, ok := registry[name]; ok {
  		panic(fmt.Sprintf("A metric with the name %q was already registered", name))
  	}
  	registry[name] = m
  }
docs: // Add adds a metric to the metric registry.
  //
  // Panics if a metric with such name is already defined.