docs: public static void register(ApiFeature apiFeature, Callback<Void, Exception> callback) {
          if (apiFeature != null && apiFeature.getApiKey() != null && !apiFeature.getApiKey().isEmpty()) {
              JavaScriptObject scriptObject = ScriptInjector.fromUrl(apiFeature.constructApiUrl())
                      .setWindow(ScriptInjector.TOP_WINDOW)
                      .setCallback(new Callback<Void, Exception>() {
                          @Override
                          public void onFailure(Exception e) {
                              callback.onFailure(e);
                          }
  
                          @Override
                          public void onSuccess(Void aVoid) {
                              callback.onSuccess(aVoid);
                          }
                      }).inject();
              features.put(apiFeature, scriptObject);
          }
      }