if r == nil {
		return nil
	}

	data := make([]byte, 4, r.Msgsize()+4)

	// Initialize the header.
	binary.LittleEndian.PutUint16(data[0:2], rebalMetaFmt)
	binary.LittleEndian.PutUint16(data[2:4], rebalMetaVer)

	buf, err := r.MarshalMsg(data)
	if err != nil {
		return err
	}

	return saveConfigWithOpts(ctx, store, rebalMetaName, buf, opts)
}