Don't end response so people can actually hook into PostRequestHandlerExecute

src/Umbraco.Web/Routing/PublishedContentNotFoundHandler.cs

@@ -44,8 +44,6 @@ namespace Umbraco.Web.Routing
 			response.Write("<p>This page can be replaced with a custom 404. Check the documentation for \"custom 404\".</p>");
 			response.Write("<p style=\"border-top: 1px solid #ccc; padding-top: 10px\"><small>This page is intentionally left ugly ;-)</small></p>");
 			response.Write("</body></html>");
-
-			response.End();
 		}
 
 		public bool IsReusable