// returns (timer owner, timer, estimated firing time) or null
static T3<O, O, Long> nextFiringTimerInVM_withOwner() {
  long time = now();
  Lowest<Pair<O>> best = new Lowest;
  for (Class c : allMainClassesAndJavaX()) {
    for (O timer : unnull(_registeredTimersOf(c))) pcall {
      long t = timer_nextFireTime(timer);
      if (t != 0)
        best.put(pair(owner, timer), t);
  }
  ret best.has() ? t3(best->a, best->b, toLong(best.bestScore())) : null;
}