Running in IIS/Express now requires calling UseIISPlatformHandlerUrl()

[Tratcher]

When running a site behind HttpPlatformHandler it specifies the dynamic port to listen on via an environment variable. In RC1 Hosting would automatically consume this variable and reconfigure the server addresses. In RC2 this logic has moved to the IWebApplicationBuilder.UseIISPlatformHandlerUrl() extension in the Microsoft.AspNet.IISPlatformHandler package. This extension replaces server.urls in the configuration to avoid conflicts with self-host configurations.

Updated entry point code:

        public static void Main(string[] args)
        {
            var hostingConfiguration = WebApplicationConfiguration.GetDefault(args);
            var application = new WebApplicationBuilder()
                        .UseConfiguration(hostingConfiguration)
                        .UseIISPlatformHandlerUrl()
                        .UseStartup<Startup>()
                        .Build();
            application.Run();
        }

Without this extension IIS will fail to load the site as it cannot contact the back-end process. The console logs will report that the site has started on the default url http://localhost:5000/ or the self-host url specified in server.urls.

See: aspnet/IISIntegration#52