code: func NewFetcher(ctx context.Context, addr storage.Address, rf RequestFunc, skipCheck bool) *Fetcher {
  	return &Fetcher{
  		addr:             addr,
  		protoRequestFunc: rf,
  		offerC:           make(chan *enode.ID),
  		requestC:         make(chan uint8),
  		searchTimeout:    defaultSearchTimeout,
  		skipCheck:        skipCheck,
  		ctx:              ctx,
  	}
  }
docs: // NewFetcher creates a new Fetcher for the given chunk address using the given request function.