async function syncAllUsers() {
    try {
      const users = await gladys.user.get();
      const service = await gladys.service.getLocalServiceByName('caldav');

      await Promise.map(
        users,
        async (user) => {
          const caldavUrl = await gladys.variable.getValue('CALDAV_URL', service.id, user.id);
          if (caldavUrl) {
            await calDavHandler.syncUserCalendars(user.id);
          }
          return null;
        },
        { concurrency: 2 },
      );
    } catch (e) {
      logger.error(e);
    }
  }
@public
@description This function sync calendars for all users.
@example
gladys.services.caldav.syncAllUsers();