Call action with each entry in this linked list.
It's an error if action modify the linked list.
Source
void forEach(void action(E entry)) {
int modificationCount = _modificationCount;
if (isEmpty) return;
E current = _first;
do {
action(current);
if (modificationCount != _modificationCount) {
throw new ConcurrentModificationError(this);
}
current = current._next;
} while (!identical(current, _first));
}