Don't set them here, since we want
        // these to overwrite defaults/constructor assignments
        for (let p in this.__dataHasAccessor) {
          if (this.hasOwnProperty(p)) {
            this.__dataInstanceProps = this.__dataInstanceProps || {};
            this.__dataInstanceProps[p] = this[p];
            delete this[p];
          }
        }
      }

      /**
       * Called at instance time with bag of properties that were overwritten
       * by accessors on the prototype when accessors wer