code: func (n *NetStore) Close() {
  	close(n.closeC)
  	n.store.Close()
  
  	wg := sync.WaitGroup{}
  	for _, key := range n.fetchers.Keys() {
  		if f, ok := n.fetchers.Get(key); ok {
  			if fetch, ok := f.(*fetcher); ok {
  				wg.Add(1)
  				go func(fetch *fetcher) {
  					defer wg.Done()
  					fetch.cancel()
  
  					select {
  					case <-fetch.deliveredC:
  					case <-fetch.cancelledC:
  					}
  				}(fetch)
  			}
  		}
  	}
  	wg.Wait()
  }
docs: // Close chunk store