code: func contentReadSeekerCloser(r resource.Resource) (hugio.ReadSeekCloser, error) {
  	switch rr := r.(type) {
  	case resource.ReadSeekCloserResource:
  		rc, err := rr.ReadSeekCloser()
  		if err != nil {
  			return nil, err
  		}
  		return rc, nil
  	default:
  		return nil, fmt.Errorf("cannot transform content of Resource of type %T", r)
  
  	}
  }
docs: // contentReadSeekerCloser returns a ReadSeekerCloser if possible for a given Resource.