anchor.diff:      _prepare(8, 1 + values.length);
       Offset result = new Offset(_tail);
       int tail = _tail;
  -    _setUint64AtTail(_buf, tail, values.length);
  +    _setUint32AtTail(_buf, tail, values.length);
       tail -= 8;
       for (double value in values) {
         _setFloat64AtTail(_buf, tail, value);
  
positive.code: 
    @override
    int get length {
      _length ??= bp._getUint64();
      return _length;
    }
  
  
negative.code:   static void _setUint32AtTail(ByteData _buf, int tail, int x) {
      _buf.setUint32(_buf.lengthInBytes - tail, x, Endianness.LITTLE_ENDIAN);
    }
  }
  
  /**
  