docs: void re_init(IonValue value, boolean hoisted)
      {
          _curr = null;
          _eof = false;
          _top = 0;
          if (value instanceof IonDatagram) {
              // datagrams interacting with these readers must be
              // IonContainerPrivate containers
              assert(value instanceof _Private_IonContainer);
              IonDatagram dg = (IonDatagram) value;
              _parent = dg;
              _next = null;
              _iter = dg.systemIterator(); // we want a system reader not: new Children(dg);
          }
          else {
              _parent = (hoisted ? null : value.getContainer());
              _next = (_Private_IonValue) value;
          }
      }