Function format_string

paddle/utils/string/string_helper.h:77–81

template <class... ARGS>
std::string format_string(const char* fmt, ARGS&&... args) {
  std::string str;
  format_string_append(str, fmt, args...);
  return str;
}

template <class... ARGS>
std::string format_string(const std::string& fmt, ARGS&&... args) {