static <A, B extends A> ThreadLocal<A> nuLike initializedThreadLocal(Class<B> c) {
  ret initializedThreadLocal(() -> nuInstance(c));
}

static <A> ThreadLocal<A> nuLike initializedThreadLocal(IF0<A> f) {
  ret new ThreadLocal<A>() {
    public A initialValue() {
      ret callF(f);
    }
  };
}