code: func Register(pvcLister corelisters.PersistentVolumeClaimLister,
  	pvLister corelisters.PersistentVolumeLister,
  	podLister corelisters.PodLister,
  	asw cache.ActualStateOfWorld,
  	dsw cache.DesiredStateOfWorld,
  	pluginMgr *volume.VolumePluginMgr) {
  	registerMetrics.Do(func() {
  		prometheus.MustRegister(newAttachDetachStateCollector(pvcLister,
  			podLister,
  			pvLister,
  			asw,
  			dsw,
  			pluginMgr))
  		prometheus.MustRegister(forcedDetachMetricCounter)
  	})
  }
docs: // Register registers metrics in A/D Controller.