void server() {

  send("server-heartbeat");

  while (true) { switch(read()) {
  case "client-heartbeat":
    if (!tosend_queue.empty) {
      while (!tosend_queue.empty) send(tosend_queue.nextCommand());
      continue; //dont send heartbeat if cmd sent
    }
    send("client-heartbeat-response");
  case "server-heartbeat-response":
    if (!tosend_queue.empty) {
      while (!tosend_queue.empty) send(tosend_queue.nextCommand());
      continue; //dont send heartbeat if cmd sent
    }
    send("server-heartbeat");
  case "command-response":
    send("server-heartbeat"); //чтобы не зависло read навсегда
  }}

}



void client() {

  send("client-heartbeat");

  while (true) switch(read()) {
  case "server-heartbeat":
    send("server-heartbeat-response");
  case "client-heartbeat-response":
    send("client-heartbeat");
  case "command":
    send("command-response");
  }

}