DateTime supporting microseconds

IDateTime.php

<?php

class IDateTime extends \DateTime
{
    public function __construct($time = 'now', $timezone = null)
    {
        if ($time === null || $time === 'now') {
            $ts = microtime(true);
            $micro = sprintf('%06d',($ts - floor($ts)) * 1000000);
            $time = date('Y-m-d H:i:s.' . $micro, $ts);
        }

        return parent::__construct($time, $timezone);
    }
}