remove unused code

        output_distance.resize(topk * nq);

        std::string hdr =

            "job " + std::to_string(search_job->id()) + " nq " + std::to_string(nq) + " topk " + std::to_string(topk);

        auto str = R"(s324gagbds

bbvcb\fds

b

fdb\f

e))";

        try {

            // step 2: search