/* Default on_error callback used if application has not provided one.  */
static int default_on_error(struct mqtt_client_t *self_p, int error)
/* Default on_error callback used if application has not provided one.  */
static int default_on_error(struct mqtt_client_t *self_p, int error)
{
    log_object_print(self_p->log_object_p,
                     LOG_ERROR,
                     OSTR("mqtt_client error: %d.\r\n"),
                     error);
    return (0);
}