如何在Dart中将List<Event>转换为Map<DateTime，List<Event>>？

import 'package:collection/collection.dart';

class Event {
  DateTime dateTime;
  String name;

  Event(this.dateTime, this.name);
}

void main() {
  List<Event> events = [
    Event(DateTime(2022, 1, 1), 'Event 1'),
    Event(DateTime(2022, 1, 1), 'Event 2'),
    Event(DateTime(2022, 1, 2), 'Event 3'),
    Event(DateTime(2022, 1, 3), 'Event 4'),
    Event(DateTime(2022, 1, 3), 'Event 5'),
  ];

  Map<DateTime, List<Event>> eventMap = groupBy(events, (Event event) => event.dateTime);

  eventMap.forEach((key, value) {
    print('$key: $value');
  });
}