How to setup sent callback for promiscuous mode

[Inquisitor]

In the ESP8266 Non-OS SDK API Reference, under wifi_send_pkt_freedom method it states,

Only after the previous packet was sent, and the sent callback is entered, the next packet is allowed to send. Otherwise, wifi_send_pkt_freedom will return “fail”.

How does one setup the sent callback? - I have set up espconn_regist_sentcb() before for TCP, but there does not seem to be such a method dedicated to promiscuous mode and the required espconn_regist_sentcb method requires an espconn structure that can only be configured with a TCP or UDP object. Since promiscuous mode is neither, what do I do? All examples that I have found on the Internet just brute force the wifi_send_pkt_freedom and let it fail... sometime trying multiple times immediately after each other expecting a different answer. I would rather check it being ready and only then create the message to be sent.

Thanks for your help.

[Inquisitor]

My bad - I was trying to set it up on the receiving logic side...

wifi_set_promiscuous_rx_cb(callbackListen);
wifi_promiscuous_enable(1);

... when obviously, I should have seen:

int wifi_register_send_pkt_freedom_cb(freedom_outside_cb_t cb);