int MqttClient_SetDisconnectCallback(MqttClient *client,
        MqttDisconnectCb discCb, void* ctx)
{
    if (client == NULL)
        return MQTT_CODE_ERROR_BAD_ARG;

    client->disconnect_cb = discCb;
    client->disconnect_ctx = ctx;

    return MQTT_CODE_SUCCESS;
}
int MqttClient_SetDisconnectCallback(MqttClient *client,
        MqttDisconnectCb discCb, void* ctx)
{
    if (client == NULL)
        return MQTT_CODE_ERROR_BAD_ARG;

    client->disconnect_cb = discCb;
    client->disconnect_ctx = ctx;

    return MQTT_CODE_SUCCESS;
}