docs: public boolean isInStruct()
      {
          boolean in_struct = false;
          IonType container = getContainerType();
          if (IonType.STRUCT.equals(container)) {
              if (getDepth() > 0) {
                  in_struct = true;
              }
              else {
                  assert(IonType.STRUCT.equals(_nesting_parent) == true);
              }
          }
          return in_struct;
      }