svoid stepAllWithStats(Steppable s, Long maxSteps default null) {
  if (s == null) ret;
  long n = 0;
  time {
    if (maxSteps == null)
      while ping (s.step()) ++n;
    else
      while ping (n < maxSteps && s.step()) ++n;
  }
  print(n2(n, "step") + " in " + lastTiming() + " ms");
}