code: private Map<String, Object> jsonRepresentation() {
          final Map<String, Object> json = new HashMap<>(getProperties());
          json.put(META_PROP_TYPE, TYPE_BLOB);
          if (blobDigest != null) {
              json.put(PROP_DIGEST, blobDigest);
          }
          else {
              json.put(META_PROP_DATA, getContent());
          }
          return json;
      }
docs: ---------------------------------------------