code: func NewBuddyinfoCollector() (Collector, error) {
  	desc := prometheus.NewDesc(
  		prometheus.BuildFQName(namespace, buddyInfoSubsystem, "blocks"),
  		"Count of free blocks according to size.",
  		[]string{"node", "zone", "size"}, nil,
  	)
  	fs, err := procfs.NewFS(*procPath)
  	if err != nil {
  		return nil, fmt.Errorf("failed to open procfs: %v", err)
  	}
  	return &buddyinfoCollector{fs, desc}, nil
  }
docs: // NewBuddyinfoCollector returns a new Collector exposing buddyinfo stats.