private void endListLevel() throws IOException {
            endRenderLevel(list);
            stream.flush();
            dataListListenerStack.removeFirst();
            if (parent != null)
                parent.childCompleted();
            list.close();
        }
The listener to the parent of this list, or null if this is the root
container-core/src/main/java/com/yahoo/processing/rendering/AsynchronousSectionedRenderer.java