ASP.NET MVC应用程序如何严重依赖于System.Web程序集？

I've read so many articles about OWIN and Katana, and one of the benefits of using OWIN in ASP.NET application is that when building ASP.NET application, i'm inherently bound to IIS due to the heavy dependency on System.Web assembly. In other words, the System.Web assembly by the default run on every request.I've read so many articles about OWIN and Katan