final List<Element<T>> backingList;
        final Spec<ValuePointer<?>> acceptanceSpec;
        int nextIndex = -1;
        int nextSubIndex = -1;
        int previousIndex = -1;
        int previousSubIndex = -1;
        T next;
        int expectedModCount = modCount;

        RealizedElementCollectionIterator(List<Element<T>> backingList, Spec<ValuePointer<?>> acceptanceSpec) {
            this.backingList = backingList;