class TreeItem extends Composite {

    public I addItem(final I item) {
        return addChild(item, t -> content.add(t));
    }

    public  TreeItem(final Type type,
                    final String value,
                    final String label,
                    final IsWidget icon);
      TreeItem(final Type type,
             final String value,
             final String label,
             final IsWidget icon,
             final Supplier<FlowPanel> contentProvider
    );

}