sclass Schedule<A extends Runnable> {
  Timestamp start;

  new TreeMultiMap<Seconds, A> entries;
  new TreeMap<Seconds> jumps;
  
  void add(double seconds, A a) {
    entries.put(Seconds(seconds), a);
  }
  
  void jumpFromTo(double from, double to) {
    jumps.put(Seconds(from), Seconds(to));
  }
  
  void speedUp(double factor) {
    IF1<Seconds> mod = seconds -> seconds.div(factor);
    entries = (TreeMultiMap) mapMultiMapKeys(mod, entries);
    jumps = map(mod, jumps);
  }
  
  run {
    start = tsNow();
    fire(first(entries));
  }
  
  void fire(Pair<Seconds, A> p) {
    if (p == null) ret;
    entries.removePair(p);
    sleepUntil(start.plus(p.a));
    pcallF(p.b);
    fire(first(entries));
  }
}