//自定义请求主体
"ajax": function(data, callback, settings) {
    //异步请求标识
    var draw = new Date().getTime();
    //分页请求
    $.send({
        url: url,
        params: $.extend(params, {
            pageNum: current_num,
            draw: draw
        })
    }).then(function (res) {
        /*
         * 【此时服务端会给我返回当前数据是第几页的
         * 我如何指定分页器当前current_num？？？】
         */
        var paginationRes = {
            draw: draw,
            recordsTotal: parseInt(res.total),
            recordsFiltered: parseInt(res.total),
            data: res.data,
            iDisplayLength: res.data.length
        }
        callback(paginationRes);
    });
}