prometheus/prometheus.go
func NewHandler(counter *Counter, level logging.Level) (h *Handler) {
	return &Handler{
		Counter: counter,
		Level:   level,
	}
}
func NewHandler(counter *Counter, level logging.Level) (h *Handler) {
	return &Handler{
		Counter: counter,
		Level:   level,
	}
}
// NewHandler returns new Handler instance.