code: func NewDevstatCollector() (Collector, error) {
  	return &devstatCollector{
  		bytesDesc: prometheus.NewDesc(
  			prometheus.BuildFQName(namespace, devstatSubsystem, "bytes_total"),
  			"The total number of bytes transferred for reads and writes on the device.",
  			[]string{"device"}, nil,
  		),
  		transfersDesc: prometheus.NewDesc(
  			prometheus.BuildFQName(namespace, devstatSubsystem, "transfers_total"),
  			"The total number of transactions completed.",
  			[]string{"device"}, nil,
  		),
  		blocksDesc: prometheus.NewDesc(
  			prometheus.BuildFQName(namespace, devstatSubsystem, "blocks_total"),
  			"The total number of bytes given in terms of the devices blocksize.",
  			[]string{"device"}, nil,
  		),
  	}, nil
  }
docs: // NewDevstatCollector returns a new Collector exposing Device stats.