code: public Map<String, String> rangeQueryState(String startKey, String endKey) {
          Map<String, String> retMap = new HashMap<>();
          for (Map.Entry<String, ByteString> item : rangeQueryRawState(startKey, endKey).entrySet()) {
              retMap.put(item.getKey(), item.getValue().toStringUtf8());
          }
          return retMap;
      }
docs: Given a start key and end key, this method returns a map of items with value converted to UTF-8 string.
  
  @param startKey
  @param endKey
  @return