private static int GetLinkDirection(this NodePortSet nodePortSet, PortDirection direction)
 {
     return(nodePortSet[direction].Match(disconnected => - 1, connected => (int)connected.Direction));
 }
 private static Guid GetLinkIdentifier(this NodePortSet nodePortSet, PortDirection direction)
 {
     return(nodePortSet[direction].Match(disconnected => Guid.Empty, connected => connected.LinkId.Value));
 }