code: func (d *CachedDiscoveryClient) Invalidate() {
  	d.mutex.Lock()
  	defer d.mutex.Unlock()
  
  	d.ourFiles = map[string]struct{}{}
  	d.fresh = true
  	d.invalidated = true
  }
docs: // Invalidate enforces that no cached data is used in the future that is older than the current time.