Method stringfy

benchmark/json.h:69–73

  ParseResult &operator=(const ParseResult &) = delete;

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

  std::unique_ptr<SR> prettify() const {
    std::unique_ptr<SR> sr = std::make_unique<SR>();