code: func (a *API) NewFeedManifest(ctx context.Context, feed *feed.Feed) (storage.Address, error) {
  	var manifest Manifest
  	entry := ManifestEntry{
  		Feed:        feed,
  		ContentType: FeedContentType,
  	}
  	manifest.Entries = append(manifest.Entries, entry)
  	data, err := json.Marshal(&manifest)
  	if err != nil {
  		return nil, err
  	}
  	addr, wait, err := a.Store(ctx, bytes.NewReader(data), int64(len(data)), false)
  	if err != nil {
  		return nil, err
  	}
  	err = wait(ctx)
  	return addr, err
  }
docs: // Manifest hack for supporting Swarm feeds from the bzz: scheme
  // see swarm/api/api.go:API.Get() for more information