static L<WebSocketHTTPD> serveHttpWithWebsockets_multiplePorts_servers = synchroList();

// factory: func(NanoHTTPD.IHTTPSession) -> WebSocket
static void serveHttpWithWebsockets_multiplePorts(O factory, int... ports) ctex {
  for (int port : ports) {
    WebSocketHTTPD httpd = new WebSocketHTTPD(port, factory);
    serveHttpWithWebsockets_multiplePorts_servers.add(httpd);
    httpd.start();
  }
}

static void cleanMeUp_serveHttpWithWebsockets_multiplePorts() {
  for (WebSocketHTTPD httpd : cloneList(serveHttpWithWebsockets_multiplePorts_servers)) {
    pcall { httpd.stop(); }
    serveHttpWithWebsockets_multiplePorts_servers.remove(httpd);
  }
}

Began life as a copy of #1011858