code: function recordInsertBefore(node, container, ref_node) {
      var this$1 = this;
  
      container.__dom.childNodes = null;
      // handle document fragments
      if (node.nodeType === Node.DOCUMENT_FRAGMENT_NODE) {
        var c$ = tree.arrayCopyChildNodes(node);
        for (var i=0; i < c$.length; i++) {
          this$1._linkNode(c$[i], container, ref_node);
        }
        // cleanup logical dom in doc fragment.
        node.__dom = node.__dom || {};
        node.__dom.firstChild = node.__dom.lastChild = null;
        node.__dom.childNodes = null;
      } else {
        this._linkNode(node, container, ref_node);
      }
    }
docs: TODO(sorvell): may need to patch saveChildNodes iff the tree has already been distributed. NOTE: ensure `node` is patched...