std::string HttpDate() {
  std::time_t t = std::time(nullptr);
  std::tm gmt = *std::gmtime(&t);

  std::ostringstream date;
  date.imbue(std::locale::classic());  // Use classic C locale
  date << std::put_time(&gmt, "%a, %d %b %Y %H:%M:%S GMT");
  return date.str();
}
std::string HttpDate() {
  std::time_t t = std::time(nullptr);
  std::tm gmt = *std::gmtime(&t);

  std::ostringstream date;
  date.imbue(std::locale::classic());   
  date << std::put_time(&gmt, "%a, %d %b %Y %H:%M:%S GMT");
  return date.str();
}