Method c_str

include/xgboost/string_view.h:50–50

    return {str_ + beg, len};
  }
  [[nodiscard]] value_type const* c_str() const { return str_; }  // NOLINT

  [[nodiscard]] constexpr const_iterator cbegin() const { return str_; }         // NOLINT
  [[nodiscard]] constexpr const_iterator cend() const { return str_ + size(); }  // NOLINT