docs: public MessageBuffer readPayloadAsReference(int length)
              throws IOException
      {
          int bufferRemaining = buffer.size() - position;
          if (bufferRemaining >= length) {
              MessageBuffer slice = buffer.slice(position, length);
              position += length;
              return slice;
          }
          MessageBuffer dst = MessageBuffer.allocate(length);
          readPayload(dst, 0, length);
          return dst;
      }