code: func NewDiscovery(conf *SDConfig, logger log.Logger) *Discovery {
  	if logger == nil {
  		logger = log.NewNopLogger()
  	}
  
  	disc := &Discovery{
  		paths:      conf.Files,
  		interval:   time.Duration(conf.RefreshInterval),
  		timestamps: make(map[string]float64),
  		logger:     logger,
  	}
  	fileSDTimeStamp.addDiscoverer(disc)
  	return disc
  }
docs: // NewDiscovery returns a new file discovery for the given paths.