clone method

Implementation

RelationshipMeta<T> clone({RelationshipMeta? parent}) {
  final meta = RelationshipMeta<T>(
    name: name,
    type: type,
    kind: kind,
    instance: instance,
  );
  if (parent != null) {
    meta.parent = parent;
    meta.parent!.child = meta; // automatically set child
  }
  return meta;
}