code: public static CompletionStage<Stage> stageOf(final String title, final Pane rootPane) {
          return FxAsync.computeOnFxThread(
              Tuple.of(title, rootPane),
              titleAndPane -> {
                  final Stage stage = new Stage(StageStyle.DECORATED);
                  stage.setTitle(title);
                  stage.setScene(new Scene(rootPane));
                  return stage;
              }
          );
      }
docs: Creates a Stage.
  
  @param title    The title of the stage
  @param rootPane The scene's base
  
  @return A {@link CompletionStage} to have monitoring over the state of the asynchronous creation. It will
  eventually contain the newly created stage.