private int depth() {
		if (depth < 0) {
			TreePath treePath = getTreePath();
			Object[] path = treePath.getPath();
			depth = path.length;
		}
		return depth;
	}
Returns true if the reference associated with this node is a call reference type.
@return true if the reference associated with this node is a call reference type.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/calltree/CallNode.java