code: public FxmlLoadResult<NODE, CONTROLLER> afterNodeLoaded(final Consumer<NODE> onNodeLoaded) {
          ensureCorrectlyLoaded();
          return new FxmlLoadResult<>(
              node.map(val -> {
                  onNodeLoaded.accept(val);
                  return val;
              }),
              controller
          );
      }
docs: Applies the given {@link Consumer} to the wrapped {@link Node} if its load (and its controller's) was
  successful.
  
  @param onNodeLoaded The post-processing to execute on the node
  
  @return A new instance of {@link FxmlLoadResult} with updated internal state.