@Override
    public StringBuilder toString(StringBuilder b, SerializationContext context, Deque<String> path, CompositeNode parent) {
        b.append("onnx_expression_node(").append(model.name()).append(")");
        if (outputAs != null && ! outputAs.equals("")) {
            b.append(".").append(outputAs);
        }
        return b;
    }
make it possible to evaluate an ONNX model anywhere in the ranking expression tree
model-evaluation/src/main/java/ai/vespa/models/evaluation/OnnxExpressionNode.java