Method new_handle

imperative/src/impl/ops/rng.cpp:21–24

    template <typename... Args>
    Handle new_handle(Args&&... args) {
        return static_cast<HandleFactory*>(this)->do_new_handle(
                std::forward<Args>(args)...);
    }

    size_t delete_handle(Handle handle) {
        size_t removed = 0;