MQTT问题

是否存在c->ping_outstanding = 1;的后一秒就触发TimerIsExpired(&c->last_received)

int keepalive(MQTTClient *c)
{
    int rc = SUCCESS;

    if (c->keepAliveInterval == 0)
        goto exit;

    if (TimerIsExpired(&c->last_sent) || TimerIsExpired(&c->last_received))
    {
        if (c->ping_outstanding)
            rc = FAILURE; /* PINGRESP not received in keepalive interval */
        else
        {
            Timer timer;
            TimerInit(&timer);
            TimerCountdownMS(&timer, 1000);
            int len = MQTTSerialize_pingreq(c->buf, c->buf_size);
            if (len > 0 && (rc = sendPacket(c, len, &timer)) == SUCCESS) // send the ping packet
                c->ping_outstanding = 1;
        }
    }

exit:
    return rc;
}