Get time in uS since powerup

int64_t esp_timer_get_time()

esp_timer_get_time() returns 64-bit time since startup, in microseconds.
int64 = 292,471 years before overflow at uS resolution!

Unlike gettimeofday function, values returned by esp_timer_get_time() start from zero after startup of the chip wakes up from deep sleep and do not have timezone or DST adjustments applied.