public virtual TResult VisitNode(RowEventNodeViewModel rowEventNode, TInput input) => DefaultVisit(rowEventNode, input);
 public virtual TResult VisitNode(RowEventNodeViewModel rowEventNode) => DefaultVisit(rowEventNode);
 public virtual IEnumerable <TreeNodeViewModel> VisitNodeAndBuildChildren(RowEventNodeViewModel rowEventNode, bool expandChildren,
                                                                          CancellationToken cancellation) =>
 Enumerable.Empty <TreeNodeViewModel>();