code: protected Map<String, Object> bytesMapToDocument(Map<String, byte[]> data) {
          if (data == null || data.size() == 0) {
              return null;
          }
          Map<String, Object> doc = new HashMap<>();
          data.forEach((k, v) -> {
              Object value = SerializationUtils.fromByteArrayFst(v);
              if (value != null) {
                  doc.put(k, value);
              }
          });
          return doc;
      }
docs: De-serialize byte-array map to "document".
  
  @param data
  @return