code: private void decodeSubscription(ByteBuf in, SubscribeMessage message) throws UnsupportedEncodingException {
          String topic = Utils.decodeString(in);
          byte qos = (byte)(in.readByte() & 0x03);
          message.addSubscription(new SubscribeMessage.Couple(qos, topic));
      }
docs: Populate the message with couple of Qos, topic