pub(crate) fn systimer_count() -> u64 {
    esp_hal::time::Instant::now()
        .duration_since_epoch()
        .as_micros()
}
Current systimer count value
A tick is 1 / 1_000_000 seconds
This function must not be called in a critical section. Doing so may return
an incorrect value.
esp-wifi/src/time.rs