static S makePostData(Map<O, O> map) {
  new L<S> l;
  for (Map.Entry<O, O> e : map.entrySet()) {
    S key = cast e.getKey();
    O val = e.getValue();
    if (val != null) {
      S value = str(val); //structureOrText(val);
      l.add(urlencode(key) + "=" + urlencode(/*escapeMultichars*/(value)));
    }
  }
  ret join("&", l);
}

static S makePostData(O... params) {
  ret makePostData(litorderedmap(params));
}