code: func NewNFSdCollector() (Collector, error) {
  	fs, err := procfs.NewFS(*procPath)
  	if err != nil {
  		return nil, fmt.Errorf("failed to open procfs: %v", err)
  	}
  
  	return &nfsdCollector{
  		fs: fs,
  		requestsDesc: prometheus.NewDesc(
  			prometheus.BuildFQName(namespace, nfsdSubsystem, "requests_total"),
  			"Total number NFSd Requests by method and protocol.",
  			[]string{"proto", "method"}, nil,
  		),
  	}, nil
  }
docs: // NewNFSdCollector returns a new Collector exposing /proc/net/rpc/nfsd statistics.