func NewCounterVec(opts prometheus.CounterOpts, labelNames []string) *prometheus.CounterVec {
	return With(prometheus.DefaultRegisterer).NewCounterVec(opts, labelNames)
}
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.
package promauto
import "github.com/prometheus/client_golang/prometheus"
func NewCounter(opts prometheus.CounterOpts) prometheus.Counter {
	return With(prometheus.DefaultRegisterer).NewCounter(opts)
}