message: add data reader
diff: @@ -287,6 +287,9 @@ impl<'a> IndexedNode<'a> {
  self.node
  }
  + pub fn data(&self) -> &NodeData {
  + &self.node.data
  + }
  }
  fn combine_nodes<'a>(left: IndexedNode<'a>, right: IndexedNode<'a>) -> Entry {
  