public TraceNode root() {
        TraceNode node = this;
        while (node.parent != null) {
            node = node.parent;
        }
        return node;
    }
<p>Returns the root <code>TraceNode</code> of the tree that this <code>TraceNode</code> belongs to.</p>

@return the root
vespajlib/src/main/java/com/yahoo/yolean/trace/TraceNode.java