transient srecord noeq G22NetworkInstance(G22Network network) {
  new Map<S, O> elementsByIdentifier;
  new Map<G22NetworkElement, O> elementsByBlueprint;
  
  void init {
    for (e : network.elements) {
      O instance = e.makeInstance();
      if (instance != null) {
        elementsByBlueprint.put(e, instance);
        mapPut(elementsByIdentifier, e.identifier(), instance);
      }
    }
  }
}