Update sample to add a README.md file

samples/ResponseCachingSample/README.md

@@ -0,0 +1,6 @@
+ASP.NET Core Response Caching Sample
+===================================
+
+This sample illustrates the usage of ASP.NET Core response caching middleware. The application sends a `Hello World!` message and the current time along with a `Cache-Control` header to configure caching behavior. The application also sends a `Vary` header to configure the cache to serve the response only if the `Accept-Encoding` header of subsequent requests matches that from the original request.
+
+When running the sample, a response will be served from cache when possible and will be stored for up to 10 seconds.

samples/ResponseCachingSample/Startup.cs

@@ -28,7 +28,7 @@ namespace ResponseCachingSample
                     Public = true,
                     MaxAge = TimeSpan.FromSeconds(10)
                 };
-                context.Response.Headers[HeaderNames.Vary] = new string[] { "Accept-Encoding", "Non-Existent" };
+                context.Response.Headers[HeaderNames.Vary] = new string[] { "Accept-Encoding" };
 
                 await context.Response.WriteAsync("Hello World! " + DateTime.UtcNow);
             });