/// <summary>
/// Called on each root vertex change.
/// </summary>
/// <param name="args"><see cref="EventArgs.Empty"/>.</param>
protected virtual void OnRootVertexChanged([NotNull] EventArgs args)
{
if (args is null)
{
throw new ArgumentNullException(nameof(args));
}
RootVertexChanged?.Invoke(this, args);
}
/// <summary>
/// Called on each root vertex change.
/// </summary>
/// <param name="args"><see cref="F:EventArgs.Empty"/>.</param>
protected virtual void OnRootVertexChanged([NotNull] EventArgs args)
{
Debug.Assert(args != null);
RootVertexChanged?.Invoke(this, args);
}