Server error if the message in an AU request was too large

var oldAu = {};
    zk.override(zAu, oldAu, {
        sendNow: function (dt) {
            zk.log('=============== fix Keikai 54');
            // KEIKAI-54
            if (!zk.mounting && dt._aureqs.length > 50) {
                var size = 20,
                    data = dt._aureqs,
                    start = 0,
                    result = true;
                while (true) {
                    dt._aureqs = data.slice(start, start + size);
                    if (!dt._aureqs.length) break;

                    if (!oldAu.sendNow(dt)) {
                        result = false;
                        break;
                    }
                    start += size;
                }
                if (start > 0 && start < data.length) {
                    dt._aureqs = data.slice(start);
                }
                return result;
            } else {
                return oldAu.sendNow(dt);
            }
        }
    });