docs: public static <T extends Collection<Integer>> T unmarshallIntCollection(ObjectInput in, CollectionBuilder<Integer, T> builder) throws IOException {
        final int size = unmarshallSize(in);
        if (size == NULL_VALUE) {
           return null;
        }
        T collection = Objects.requireNonNull(builder, "CollectionBuilder must be non-null").build(size);
        for (int i = 0; i < size; ++i) {
           collection.add(in.readInt());
        }
        return collection;
     }