code: private void sendRequestHeader(MessageType type, int size) throws IOException {
      ByteBuffer buf = ByteBuffer.allocate(8);
      buf.order(ByteOrder.BIG_ENDIAN);
      buf.put((byte) 'L');
      buf.put((byte) '1');
      buf.put(type.getValue());
      buf.put((byte) 0);  // request
      buf.putInt(size);
      buf.flip();
      logger.finest("SEND: type=" + (0) + ", command=" + ((int) type.getValue()) + ", size=" + size);
      os.write(buf.array());
    }
docs: Send the 8 byte header before a Opera Launcher message body (payload).
  
  @param type the payload type to be sent after
  @param size size of the payload following the header
  @throws IOException if socket send error or protocol parse error