code: static String encode(ByteBufferRange range) {
          String start = Hex.encodeHexString(toArray(range.getStart()));
          String end = Hex.encodeHexString(toArray(range.getEnd()));
          int prefix = getCommonPrefixLength(start, end);
          return start.substring(0, prefix) + ':' + start.substring(prefix) + '-' + end.substring(prefix);
      }
docs: Returns a string that looks like "commonPrefix:startSuffix-endSuffix", hex-encoding the bytes.