code: func (v *HistogramVec) With(labels Labels) Observer {
  	h, err := v.GetMetricWith(labels)
  	if err != nil {
  		panic(err)
  	}
  	return h
  }
docs: // With works as GetMetricWith but panics where GetMetricWithLabels would have
  // returned an error. Not returning an error allows shortcuts like
  //     myVec.With(prometheus.Labels{"code": "404", "method": "GET"}).Observe(42.21)