docs: def nl_msg_out_handler_debug(msg, arg):
      """https://github.com/thom311/libnl/blob/libnl3_2_25/lib/handlers.c#L124."""
      ofd = arg or _LOGGER.debug
      ofd('-- Debug: Sent Message:')
      nl_msg_dump(msg, ofd)
      return NL_OK