ZMQ_HELLO_MSG doesn't work

[wsehjk]

Please use this template for reporting suspected bugs or requests for help.

Issue description

server socket (router mode) set the ZMQ_HELLO_MSG, but the client (dealer mode) cannnot receive this msg, even though netstat says connection has been established.

Environment

• libzmq version (commit hash if unreleased): 4.3.4
• OS: macos Monterey 12.5.1, vscode 1.84.2 (Universal)

Minimal test code / Steps to reproduce the issue

#define ZMQ_BUILD_DRAFT_API
#include <iostream>
#include <zmq.hpp>

int main() {
    zmq::context_t server_ctx;
    zmq::context_t client_ctx;

    zmq::socket_t server(server_ctx, zmq::socket_type::router);
    zmq::socket_t client(client_ctx, zmq::socket_type::dealer);
    zmq_setsockopt(server, ZMQ_HELLO_MSG, "hello", 5);

    client.setsockopt(ZMQ_RCVTIMEO, 80000); // 500ms

    server.bind("tcp://127.0.0.1:5555");
    client.connect("tcp://127.0.0.1:5555");
    zmq::message_t msg;

    while (true) {
        client.recv(msg);
        if (!msg.empty()) {
            std::string str(msg.to_string());
            std::cout << str << std::endl;
            break;
        }
    }
    return 0;
}

What's the actual result? (include assertion message & call stack if applicable)

should print hello

What's the expected result?

program stuck in the while loop