如何定义一个有效的OWIN Startup Class

<add key="owin:appStartup" value="OwinConsoleApp.Startup1" />

<appSettings>  
  <add key="owin:appStartup" value="ProductionConfiguration" />       
</appSettings>

[assembly: OwinStartup("ProductionConfiguration", typeof(StartupDemo.ProductionStartup2))]

namespace StartupDemo
{
    public class ProductionStartup
    {
        public void Configuration(IAppBuilder app)
        {
            app.Run(context =>
            {
                string t = DateTime.Now.Millisecond.ToString();
                return context.Response.WriteAsync(t + " Production OWIN App");
            });
        }
    }
    public class ProductionStartup2
    {
        public void Configuration(IAppBuilder app)
        {
            app.Run(context =>
            {
                string t = DateTime.Now.Millisecond.ToString();
                return context.Response.WriteAsync(t + " 2nd Production OWIN App");
            });
        }
    }
}