docs: public void writeEmptyPacket() throws IOException {
      buf[0] = (byte) 4;
      buf[1] = (byte) 0x00;
      buf[2] = (byte) 0x00;
      buf[3] = (byte) this.compressSeqNo++;
      buf[4] = (byte) 0x00;
      buf[5] = (byte) 0x00;
      buf[6] = (byte) 0x00;
      buf[7] = (byte) 0x00;
      buf[8] = (byte) 0x00;
      buf[9] = (byte) 0x00;
      buf[10] = (byte) this.seqNo++;
      out.write(buf, 0, 11);
  
      if (traceCache != null) {
        traceCache.put(new TraceObject(true, COMPRESSED_PROTOCOL_NOT_COMPRESSED_PACKET,
            Arrays.copyOfRange(buf, 0, 11)));
      }
  
      if (logger.isTraceEnabled()) {
        logger.trace("send uncompress:{}{}",
            serverThreadLog,
            Utils.hexdump(maxQuerySizeToLog, 0, 11, buf));
      }
    }