Method doHEAD

test/doc/http_examples.cpp:191–211

    }

    void
    doHEAD()
    {
        test::stream ts{ioc_}, tr{ioc_};
        ts.connect(tr);
        yield_to(
            [&](yield_context)
            {
                error_code ec;
                flat_buffer buffer;
                do_server_head(tr, buffer, ec);
                BEAST_EXPECTS(! ec, ec.message());
            },
            [&](yield_context)
            {
                error_code ec;
                flat_buffer buffer;
                auto res = do_head_request(ts, buffer, "/", ec);
                BEAST_EXPECTS(! ec, ec.message());
            });
    }

    struct handler
    {