@Override
 public void encode(OutputStream output) throws IOException {
   // 2
   output.write(
       ByteArrayBuilder.parseShort(
           HtunAttribute.UNKNOWN_ATTRIBUTE, ByteArrayBuilder.BYTEORDER_BIG_ENDIAN));
   // length 2*type size
   int length = mTypes.size() * 2;
   output.write(ByteArrayBuilder.parseShort(2, ByteArrayBuilder.BYTEORDER_BIG_ENDIAN));
   // value
   for (Integer type : mTypes) {
     output.write(ByteArrayBuilder.parseShort(type, ByteArrayBuilder.BYTEORDER_BIG_ENDIAN));
   }
 }