Do websocat handle closing handshake properly with a websocketpp server? - c++

Question

I'm running a websocket server with websocketpp. For applicative reasons, the server may close the connection. When I connect to the server with websocat and the server closes the connection it seems that the closing handshake times out, and the on_close handler is called.
Do you know if websocat handles the closing handshake properly ? (it would be weird if it didn't)
Note : I didn't test with another websocket client.
Am I doing something wrong when closing the connection ?
Why is the on_close handler is called when the closing handshake times out ?
The server code:
#include <thread>
#include <websocketpp/config/asio.hpp>
#include <websocketpp/server.hpp>
#include <iostream>
typedef websocketpp::server<websocketpp::config::asio> server;
using websocketpp::lib::placeholders::_1;
void on_open_connection(server * srv, websocketpp::connection_hdl hdl) {
using namespace std::chrono_literals;
using namespace websocketpp::close::status;
std::this_thread::sleep_for(3s);
auto conn = srv->get_con_from_hdl(hdl);
conn->close(normal, get_string(normal));
}
void on_close(websocketpp::connection_hdl hdl) {
std::cout << "On close" << std::endl;
}
int main() {
server closing_server;
closing_server.init_asio();
closing_server.set_open_handler(std::bind(&on_open_connection, &closing_server, ::_1));
closing_server.set_close_handler(std::bind(&on_close, ::_1));
closing_server.listen(9002);
closing_server.start_accept();
closing_server.run();
}