Set schedule at given timezone

I am using flutter_local_notifications and timezone to create schedule notification.

My question is how can I set schedule notification as per given timezone.

For exp, I am in India and I want to set timezone as per pakistan/karachi, now whenever I select time as per karachi timezone then I am facing error Invalid argument (scheduledDate): Must be a date in the future

How can I schedule notification as per given timezone to local timezone?

here is my code sample.

   tz.initializeTimeZones();
    var karachiTime = tz.getLocation('Asia/Karachi');
    tz.setLocalLocation(karachiTime);
    
        try {
      await flutterLocalNotificationsPlugin!.zonedSchedule(1, 'Reminder', "Reminder",
          tz.TZDateTime.from(tzDateTime, karachiTime), NotificationService.scheduleNotificationDetails,
          androidAllowWhileIdle: true,
          payload: tempPayload,
          uiLocalNotificationDateInterpretation: UILocalNotificationDateInterpretation.absoluteTime);
      print("Next Schedule: " + tzDateTime.toString());
    } catch (e) {
      print("Schedule Error: " + e.toString());
    }

Thanks in Advance!