std::formatter::format(C++20)

template <class FormatContext>
typename FormatContext::iterator
format(const chrono::zoned_time<Duration, TimeZonePtr>& tp,
       FormatContext& ctx);                                 // (1) C++20

sys_info info = tp.get_info();
chrono::local-time-format-t<Duration> x {
  tp.get_local_time(),
  &info.abbrev,
  &info.offset
};

return formatter<chrono::local-time-format-t<Duration>, charT>::format(
    x,
    ctx
);