Where is MVCSerializer.Deserialize()?

I cannot find this library anywhere. I googled MVCSerializer I didn't get any valid results. I'm trying to use [Deserialize] in front of a controller action parameter.

   [Ht开发者_Go百科tpPost]
    public ActionResult Step2(Step2ViewModel step2, [Deserialize] Step1ViewModel step1)
    {
        var model = new WizardViewModel
        {
            Step1 = step1,
            Step2 = step2
        };

        if (!ModelState.IsValid)
        {
            return View(model);
        }
        return View("Step3", model);
    }

This can be found in the MVC futures assembly:

http://aspnet.codeplex.com/releases/view/58781#DownloadId=211128