void addOutputMapping(String onnxName, String outputAs) {
        if (evaluator != null)
            throw new IllegalStateException("output mapping must be added before load()");
        outputSpecs.add(new OutputSpec(onnxName, outputAs));
    }
A named ONNX model that should be evaluated with OnnxEvaluator.

@author lesters
model-evaluation/src/main/java/ai/vespa/models/evaluation/OnnxModel.java