How to customize the blackout dates in the Flutter event calendar (SfCalendar) ?

child: SfCalendar(
  view: CalendarView.month,
  allowedViews: <CalendarView>[
    CalendarView.month,
    CalendarView.timelineMonth
  ],
  dataSource: _getDataSource(),
  blackoutDates: <DateTime>[
    DateTime.now().add(Duration(days: 1)),
    DateTime.now().add(Duration(days: 2))
  ],
  blackoutDatesTextStyle: TextStyle(
      fontWeight: FontWeight.w400,
      fontSize: 13,
      color: Colors.pinkAccent,
      decoration: TextDecoration.lineThrough),
),

import 'package:flutter/material.dart';
import 'package:flutter/widgets.dart';
import 'package:syncfusion_flutter_calendar/calendar.dart';
 
void main() => runApp(BlackoutDatesCustomization());
 
class BlackoutDatesCustomization extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
        debugShowCheckedModeBanner: false,
        home: Scaffold(
            body: SafeArea(
          child: SfCalendar(
            view: CalendarView.month,
            allowedViews: <CalendarView>[
              CalendarView.month,
              CalendarView.timelineMonth
            ],
            dataSource: _getDataSource(),
            blackoutDates: <DateTime>[
              DateTime.now().add(Duration(days: 1)),
              DateTime.now().add(Duration(days: 2))
            ],
            blackoutDatesTextStyle: TextStyle(
                fontWeight: FontWeight.w400,
                fontSize: 13,
                color: Colors.pinkAccent,
                decoration: TextDecoration.lineThrough),
          ),
        )));
  }
 
  _DataSource _getDataSource() {
    final List<Appointment> appointments = <Appointment>[];
    appointments.add(Appointment(
      startTime: DateTime.now().add(Duration(hours: 4)),
      endTime: DateTime.now().add(Duration(hours: 5)),
      subject: 'Meeting',
      color: Colors.red,
    ));
    appointments.add(Appointment(
      startTime: DateTime.now().add(Duration(days: -2, hours: 4)),
      endTime: DateTime.now().add(Duration(days: -2, hours: 5)),
      subject: 'Development Meeting   New York, U.S.A',
      color: Color(0xFFf527318),
    ));
    appointments.add(Appointment(
      startTime: DateTime.now().add(Duration(days: -2, hours: 3)),
      endTime: DateTime.now().add(Duration(days: -2, hours: 4)),
      subject: 'Project Plan Meeting   Kuala Lumpur, Malaysia',
      color: Color(0xFFfb21f66),
    ));
    appointments.add(Appointment(
      startTime: DateTime.now().add(Duration(days: -2, hours: 2)),
      endTime: DateTime.now().add(Duration(days: -2, hours: 3)),
      subject: 'Support - Web Meeting   Dubai, UAE',
      color: Color(0xFFf3282b8),
    ));
    appointments.add(Appointment(
      startTime: DateTime.now().add(Duration(days: -2, hours: 1)),
      endTime: DateTime.now().add(Duration(days: -2, hours: 2)),
      subject: 'Project Release Meeting   Istanbul, Turkey',
      color: Color(0xFFf2a7886),
    ));
    appointments.add(Appointment(
        startTime: DateTime.now().add(const Duration(hours: 4, days: -1)),
        endTime: DateTime.now().add(const Duration(hours: 5, days: -1)),
        subject: 'Release Meeting',
        color: Colors.lightBlueAccent,
        isAllDay: true));
    appointments.add(Appointment(
      startTime: DateTime.now().add(const Duration(hours: 2, days: -4)),
      endTime: DateTime.now().add(const Duration(hours: 4, days: -4)),
      subject: 'Performance check',
      color: Colors.amber,
    ));
    appointments.add(Appointment(
      startTime: DateTime.now().add(const Duration(hours: 11, days: -2)),
      endTime: DateTime.now().add(const Duration(hours: 12, days: -2)),
      subject: 'Customer Meeting   Tokyo, Japan',
      color: Color(0xFFffb8d62),
    ));
    appointments.add(Appointment(
      startTime: DateTime.now().add(const Duration(hours: 6, days: 2)),
      endTime: DateTime.now().add(const Duration(hours: 7, days: 2)),
      subject: 'Retrospective',
      color: Colors.purple,
    ));
 
    return _DataSource(appointments);
  }
}
 
class _DataSource extends CalendarDataSource {
  _DataSource(List<Appointment> source) {
    appointments = source;
  }
}