isSameDate function
Check the dates are equal or not.
Implementation
bool isSameDate(dynamic date1, dynamic date2) {
  if (date2 == date1) {
    return true;
  }
  if (date1 == null || date2 == null) {
    return false;
  }
  if (date1 is HijriDateTime && date2 is HijriDateTime) {
    return date1.month == date2.month &&
        date1.year == date2.year &&
        date1.day == date2.day &&
        date1._date == date2._date;
  }
  return date1.month == date2.month &&
      date1.year == date2.year &&
      date1.day == date2.day;
}