docs: private void exit(String command, Socket socket) throws IOException {
          lock.lock();
          try {
               // We may exit before we get a chance to reply.
  
              DataOutputStream dout = new DataOutputStream(socket.getOutputStream());
              dout.writeInt(BYTES_INT);
              dout.writeInt(1);
              dout.flush();
  
              ClientStateMachine.exitJava();
  
          } finally {
              lock.unlock();
          }
      }