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