main.dart

void main() {  
   final now = DateTime.now();
   final offset = now.timeZoneOffset; 
   final negativeDuration = Duration(hours: -3);
   final duration = negativeDuration;  
   print(offset.isNegative);
   print(negativeDuration.isNegative);
   final date = DateTime.parse('2023-03-07 10:00').subtract(duration);
   final utcDate = date.toLocal().toLocal().copyWith(isUtc: true).toIso8601String();
   print(utcDate);
   print(DateTime.parse(utcDate).toLocal());  
}