anchor.diff:      parent.appendChild(node);
     }
   }
  +
  +enum _SyncOperation { IDENTICAL, INSERTION, STATEFUL, STATELESS, REMOVAL }
   
   /*
    * All Effen nodes derive from Node. All nodes have a _parent, a _key and
  
positive.code:     print(buffer);
    }
  
    void _removeChild(Node node) {
      _trace('_sync(remove) ${node._key}');
      node._remove();
    }
  
  
negative.code:     node._parent = this;
  
      if (oldNode == null) {
        _traceSync(_SyncOperation.INSERTION, node._key);
      } else {
        _traceSync(_SyncOperation.STATELESS, node._key);
      }
      node._sync(oldNode, host, insertBefore);
      if (oldNode != null)
  