如何在flutter中使用google日历api获取一个月内的所有活动？

import 'package:googleapis/calendar/v3.dart' as calendar;
import 'package:googleapis_auth/auth_io.dart' as auth;

void main() async {
  // 认证
  var credentials = await auth.clientViaApiKey('YOUR_API_KEY', scopes: [
    calendar.CalendarApi.calendarReadonlyScope,
  ]);

  // 创建日历服务
  var calendarClient = calendar.CalendarApi(credentials);

  // 获取当前日期和一个月后的日期
  var now = DateTime.now();
  var oneMonthLater = now.add(Duration(days: 30));

  // 格式化日期
  var formattedNow = now.toIso8601String();
  var formattedOneMonthLater = oneMonthLater.toIso8601String();

  // 获取活动列表
  var events = await calendarClient.events.list('primary',
      timeMin: formattedNow, timeMax: formattedOneMonthLater);

  // 打印活动信息
  events.items?.forEach((event) {
    print('Summary: ${event.summary}');
    print('Start: ${event.start?.dateTime}');
    print('End: ${event.end?.dateTime}');
    print('---');
  });
}