Queued save in Backbone.Model using jQuery Deferred

queuedmodel.js

var QueuedModel = Backbone.Model.extend({
    url: function () {
        var delay = Math.floor(Math.random() * 7);
        return "/echo/json/?delay=" + delay;
    },
    
    initialize : function () {
        this.saveQueue = jQuery.Deferred();
        this.saveQueue.resolve();
        
        this.on("sync", function () {
            console.log("sync");
        });
    },
    
    save: function (attrs, options) {
        var model = this;
        console.log("set " + JSON.stringify(attrs));
       
        this.saveQueue = this.saveQueue.then(function () {
            console.log("request " + JSON.stringify(attrs));
            return Backbone.Model.prototype.save.call(model, attrs, options);
        });            
    }

});

var m = new QueuedModel();
m.save({ title: "1. a title" });
m.save({ description: "2. a description" });
m.save({ title: "3. a new title" });
m.save({ price: "4. a price" });

Requires jQuery >= v1.8. If using 1.7, replace then() with pipe().