ImmutableSet.Builder<String> builder = ImmutableSet.builder();
      for (String e : elements) {
        builder.add(e);
      }
      return builder.build();
    }
  }

  public static class ImmutableSetSizedBuilderGenerator extends TestStringSetGenerator {
    @Override
    protected Set<String> create(String[] elements) {
      ImmutableSet.Builder<String> builder =