docs: private void close(String command, Socket socket) throws IOException {
          lock.lock();
          try {
              String token = command.substring(closeTagLength, command.length() - (closeTagLength + 1));
  
              initTokens.remove(token);
  
              DataOutputStream dout = new DataOutputStream(socket.getOutputStream());
              dout.writeInt(BYTES_INT);
              dout.writeInt(1);
              dout.flush();
          } finally {
              lock.unlock();
          }
      }