ChildPod<TParent extends Object, TChild extends Object>  constructor 
      
      ChildPod<TParent extends Object, TChild extends Object> ({ 
    
    
- required TPodsResponderFn<TParent> responder,
- required TValuesReducerFn<TChild, TParent> reducer,
Implementation
ChildPod({
  required TPodsResponderFn<TParent> responder,
  required TValuesReducerFn<TChild, TParent> reducer,
}) : _reducer = reducer,
     _responder = responder {
  _parents = responder();
  value = reducer(parents.map((p) => p.value).toList());
  _initializeParents(parents);
}