求助：Laravel 读取不到微秒数？

<?php
// routes.php

Route::get('/', function () {
    $test = \DB::select('select * from test');
    dd($test[0]->time);
});

CREATE TABLE `test` (
  `id` int(10) UNSIGNED NOT NULL,
  `time` datetime(3) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

INSERT INTO `test` (`id`, `time`) VALUES ('1', '2016-04-04 00:00:00.123');

输出 2016-04-04 00:00:00。如何得到微秒数，大家帮帮我