static <A> void lambdaMapLike traverseStringTrie_leavesFirst(IVF1<StringTrie<A>> visitor, StringTrie<A> trie) {
  if (trie == null || visitor == null) ret;
  for (S string, StringTrie<A> child : trie.children())
    traverseStringTrie_leavesFirst(visitor, child);
  visitor.get(trie);
}