FFI for ICU4X example

datetime.cpp

class DateTimeFormat {
  public:
    Result<DateTimeFormat, ()> tryNew(string aLocale, options aOptions);
  
    string format(date aDate);
  
  protected:
    DateTimeFormat(string aLocale, ffi::DateTimeFormatData aData);
    UniquePtr<ffi::DateTimeFormatData> mData;
};

Result<DateTimeFormat, ()>
DateTimeFormat::tryNew(string aLocale, options aOptions) {
    ffi::RequestData request = ffi::DateTimeFormat::Request(aLocale, aOptions);
    mData = ffi::DataProvider::GetData(request); // fallible? async?
    return new DateTimeFormat(aLocale, mData);
}

string
DateTimeFormat::Format(date aDate) {
    return ffi::DateTimeFormat::Format(aDate, mData);
}