static <A> IVF1<A> psCollect(IProbabilisticScheduler ps, Cl<WithProbability<A>> out) {
  ret a -> {
    if (out != null)
      out.add(withPreciseProbability(ps.currentProbability(), a));
  };
}

svoid <A> psCollect(IProbabilisticScheduler ps,
  Cl<WithProbability<A>> results_out,
  int maxResults,
  IVF1<IVF1<A>> action) {
  action.get(psCollect(ps, results_out));
  stepUntil(ps, () -> l(results_out) >= 10);
}