VPackValue for AQL exception

[Andy]

AttrbuteTranslator works, but next problem with the same example:

        timer t;

        std::cout <<  "execute 1 long query ... " << std::flush;
        auto request = f::createRequest(f::RestVerb::Post, "/_api/cursor"s);
        VPackBuilder builder;
        builder.openObject();
 -----> builder.add("query", VPackValue("LET x = SLEEP(10) RETURN 1"));
        builder.close();
        request->addVPack(builder.slice());
        auto result = connection->sendRequest(std::move(request));

        std::cout <<  "done" << std::endl;

in this line is exception