code: func (dr *DescribeRequest) Result() (desmap map[string]*DescribedBlob, err error) {
  	dr.wg.Wait()
  	// TODO: set "done" / locked flag, so no more DescribeBlob can
  	// be called.
  	if len(dr.errs) > 0 {
  		return dr.m, DescribeError(dr.errs)
  	}
  	return dr.m, nil
  }
docs: // Result waits for all outstanding lookups to complete and
  // returns the map of blobref (strings) to their described
  // results. The returned error is non-nil if any errors
  // occurred, and will be of type DescribeError.