### Question:
HelloProxyServiceImpl implements HelloProxyService { @Override public ServiceCall<NotUsed, String> proxyViaHttp(String id) { return req -> helloService.hello(id).invoke(); } @Inject  HelloProxyServiceImpl(
        HelloService helloService,
        GreeterServiceClient greeterClient); @Override ServiceCall<NotUsed, String> proxyViaHttp(String id); @Override ServiceCall<NotUsed, String> proxyViaGrpc(String id);  }### Answer:
@Test public void helloProxyShouldRoundtripHttpRequests() throws InterruptedException, ExecutionException, TimeoutException { String msg = proxyServiceClient.proxyViaHttp("Alice").invoke() .toCompletableFuture().get(5, SECONDS); assertEquals("Hello Alice", msg); }