code: func (c *Client) Download(ctx context.Context, u *url.URL, param *Download) (io.ReadCloser, int64, error) {
  	res, err := c.DownloadRequest(ctx, u, param)
  	if err != nil {
  		return nil, 0, err
  	}
  
  	switch res.StatusCode {
  	case http.StatusOK:
  	default:
  		err = errors.New(res.Status)
  	}
  
  	if err != nil {
  		return nil, 0, err
  	}
  
  	r := res.Body
  
  	return r, res.ContentLength, nil
  }
docs: // Download GETs the remote file from the given URL