docs: public static Optional<Optional<byte[]>> readMaybeOptRangedBytes(ByteBuf bf) {
        Optional<Integer> l = readMaybeSignedInt(bf);
        if (l.isPresent()) {
           int length = l.get();
           if (length < 0) {
              return Optional.of(Optional.empty());
           } else {
              Optional<byte[]> rb = readMaybeRangedBytes(bf, length);
              if (rb.isPresent()) {
                 return Optional.of(rb);
              } else {
                 return Optional.empty();
              }
           }
        } else {
           return Optional.empty();
        }
     }