/// <summary>
/// pins a node to min layer
/// </summary>
/// <param name="node"></param>
internal void PinNodeToMinLayer(Node node)
{
System.Diagnostics.Debug.Assert(node != null);
MinLayerOfGeomGraph.Insert(node);
}
internal void UnpinNodeFromMinLayer(Node node)
{
MinLayerOfGeomGraph.Remove(node);
}
