code: func (w *Writer) WriteWith(fw recordio.Writer, b *logpb.ButlerLogBundle) error {
  	data, err := proto.Marshal(b)
  	if err != nil {
  		entries := b.GetEntries()
  		// TODO(tandrii, hinoka): leave just error after crbug.com/859995 is fixed.
  		if len(entries) > 100 {
  			return fmt.Errorf("butlerproto: failed to marshal Bundle of len %d with first 100 entries %s: %s",
  				len(entries), entries[:100], err)
  		} else {
  			return fmt.Errorf("butlerproto: failed to marshal Bundle %s: %s", entries, err)
  		}
  	}
  
  	return w.writeData(fw, logpb.ButlerMetadata_ButlerLogBundle, data)
  }
docs: // WriteWith writes a ButlerLogBundle to the supplied recordio.Writer.