Method prettify

benchmark/json.h:75–79

  }

  std::unique_ptr<SR> prettify() const {
    std::unique_ptr<SR> sr = std::make_unique<SR>();
    if (sr && static_cast<const PR *>(this)->prettify_impl(*sr)) return sr;
    return nullptr;
  }

  bool stat(DocStat &stat) const {
    return static_cast<const PR *>(this)->stat_impl(stat);