Thanks, @gfvalvo
Sure, my code was just to measure
the required period somehow.
BTW: As you mention "native USB", it's interesting to me that
Serial.begin(115200);
while (!Serial) delay(10); // waiting for native USB Serial to become alive
delay (500); // You still have to wait a while on an ESP32 ...
To be clear, it's, not a problem, but just curiosity, how the multihreading OS of an ESP, or whatever (?) causes this behavior.