SMailCallbackContext.setPreparedMessageHookOnThread(notificationHelper::send);
                    EsStatusPostcard.droppedInto(postbox, postcard -> {
                        postcard.setFrom(fessConfig.getMailFromAddress(), fessConfig.getMailFromName());
                        postcard.addReplyTo(fessConfig.getMailReturnPath());

    //                                                                         Entry Point
    //                                                                         ===========
    public static TestmailPostcard droppedInto(Postbox postbox, MPCall<TestmailPostcard> postcardLambda) {
        TestmailPostcard postcard = new TestmailPostcard();
        postcardLambda.write(postcard);
        postbox.post(postcard);
        return postcard;
    }

    //                                                                         Entry Point
    //                                                                         ===========
    public static EsStatusPostcard droppedInto(Postbox postbox, MPCall<EsStatusPostcard> postcardLambda) {
        EsStatusPostcard postcard = new EsStatusPostcard();
        postcardLambda.write(postcard);
        postbox.post(postcard);
        return postcard;
    }