Bind the decoder to req.body

test/controller_test.dart

@@ -113,7 +113,7 @@ main() {
         }, optional: ['bar']));
     var rq = MockHttpRequest('GET', Uri(path: 'foo'));
     await AngelHttp(app).handleRequest(rq);
-    var body = await rq.response.transform(utf8.decoder).join();
+    var body = await utf8.decoder.bind(rq.response).join();
     expect(json.decode(body), 2);
   });
 

test/di_test.dart

@@ -28,7 +28,7 @@ main() {
     app.container.registerSingleton(Todo(text: TEXT, over: OVER));
     app.container.registerFactory<Future<Foo>>((container) async {
       var req = container.make<RequestContext>();
-      var text = await req.body.transform(utf8.decoder).join();
+      var text = await utf8.decoder.bind(req.body).join();
       return Foo(text);
     });