Mark MemoryCache as experimental

samples/volatile-cache/README.md

@@ -3,26 +3,11 @@
 To run the example on http://localhost:8080
 
 ```sh
-$ ./workerd serve config.capnp
+$ ./workerd serve --experimental config.capnp
 ```
 
 To run using bazel
 
 ```sh
-$ bazel run //src/workerd/server:workerd -- serve ~/cloudflare/workerd/samples/helloworld_esm/config.capnp
-```
-
-To create a standalone binary that can be run:
-
-```sh
-$ ./workerd compile config.capnp > helloworld
-
-$ ./helloworld
-```
-
-To test:
-
-```sh
-% curl http://localhost:8080
-Hello World
+$ bazel run //src/workerd/server:workerd -- serve ~/cloudflare/workerd/samples/helloworld_esm/config.capnp --experimental
 ```

src/workerd/server/server.c++

@@ -2423,6 +2423,11 @@ static kj::Maybe<WorkerdApi::Global> createBinding(
       return makeGlobal(Global::UnsafeEval {});
     }
     case config::Worker::Binding::MEMORY_CACHE: {
+      if (!experimental) {
+        errorReporter.addError(kj::str(
+          "MemoryCache bindings are an experimental feature which may change or go away "
+          "in the future. You must run workerd with `--experimental` to use this feature."));
+      }
       auto cache = binding.getMemoryCache();
       // TODO(cleanup): Should we have some reasonable default for these so they can
       // be optional?