code: func NewCounterVec(opts prometheus.CounterOpts, labelNames []string) *prometheus.CounterVec {
  	c := prometheus.NewCounterVec(opts, labelNames)
  	prometheus.MustRegister(c)
  	return c
  }
docs: // NewCounterVec works like the function of the same name in the prometheus
  // package but it automatically registers the CounterVec with the
  // prometheus.DefaultRegisterer. If the registration fails, NewCounterVec
  // panics.