GMDAsyncSample.java

        // Will setup the LoadResultCallback where the async widget has predefined UX upon loading the request
        // and display the callback result returned by the server
        LoadResultCallback<Car, MaterialButton> loadResultCallback = new LoadResultCallback<>(asyncButton);
        
        // Let the user decide how they perform client to server mechanism (e.g RPC).
        final CarServiceAsync carServiceAsync = GWT.create(FakeCarService.class);
        carServiceAsync.getCar(1, new AsyncCallback<Car>() {
            @Override
            public void onFailure(Throwable throwable) {
                loadResultCallback.onFailure(throwable);
            }

            @Override
            public void onSuccess(Car car) {
                loadResultCallback.onSuccess(car);
            }
        });
        
        // Will perform the async load() method and call the asynccallback
        loadResultCallback.load();