In MQTT example I see this headers:
 
extern “C” {
  #include “freertos/FreeRTOS.h”
  #include “freertos/timers.h”
}

 
I’m read that ESP32 use multitasking operation system FreeRTOS.
 
For example (as we can see at MQTT code) FreeRTOS proposes this timer functions:

xTimerCreate

xTimerStart
xTimerStop

 
FreeRTOS can create and manage tasks also.
 
At this time I develop simple module, based on ESP32 that have for independent relay, each relay must circle on/off according to it’s timer setting. At project I plan to use xTimerCreate and so on functions.
 
But it’s very intresting if you add to ESP32 course FreeRTOS explanation with examples 🙂