response.addAttribute(MailService.A_CHANGE_DATE, System.currentTimeMillis() / 1000);
    public Element handle(Element request, Map context) throws ServiceException {        ZimbraContext lc = getZimbraContext(context);        Mailbox mbox = getRequestedMailbox(lc);        long begin = request.getAttributeLong(MailService.A_TOKEN, 0);        Element response = lc.createElement(MailService.SYNC_RESPONSE);        synchronized (mbox) {            mbox.beginTrackingSync();            long token = mbox.getLastChangeID();            response.addAttribute(MailService.A_TOKEN, token);            if (begin <= 0) {                Folder folder = mbox.getFolderById(DEFAULT_FOLDER_ID);                if (folder == null)                    throw MailServiceException.NO_SUCH_FOLDER(DEFAULT_FOLDER_ID);                initialFolderSync(response, mbox, folder);            } else                deltaSync(response, mbox, begin);        }        return response;    }