code: public String getHexDump() {
          if (_buf.position() == _buf.limit()) {
              return "empty";
          }
  
          StringBuilder hexDump = new StringBuilder();
          for (int i = _buf.position(); i < _buf.limit(); i++) {
              hexDump.append(Integer.toHexString(_buf.get(i)&0xFF)).append(' ');
          }
          return hexDump.toString();
      }
docs: Returns a hex dump of this buffer.
  
  @return the hex dump