| lwIP
    2.0.3
    Lightweight IP stack | 
#include <mqtt.h>
| Data Fields | |
| struct mqtt_request_t * | next | 
| mqtt_request_cb_t | cb | 
| u16_t | pkt_id | 
| u16_t | timeout_diff | 
Pending request item, binds application callback to pending server requests
| mqtt_request_cb_t mqtt_request_t::cb | 
Callback to upper layer
| struct mqtt_request_t* mqtt_request_t::next | 
Next item in list, NULL means this is the last in chain, next pointing at itself means request is unallocated
| u16_t mqtt_request_t::pkt_id | 
MQTT packet identifier
| u16_t mqtt_request_t::timeout_diff | 
Expire time relative to element before this