code: public static int encodeDesc(Byte value, byte[] dst, int dstOffset) {
          if (value == null) {
              dst[dstOffset] = NULL_BYTE_LOW;
              return 1;
          } else {
              dst[dstOffset] = NOT_NULL_BYTE_LOW;
              dst[dstOffset + 1] = (byte)(value ^ 0x7f);
              return 2;
          }
      }
docs: Encodes the given signed Byte object into exactly 1 or 2 bytes for
  descending order. If the Byte object is never expected to be null,
  consider encoding as a byte primitive.
  
  @param value optional signed Byte value to encode
  @param dst destination for encoded bytes
  @param dstOffset offset into destination array
  @return amount of bytes written