constructor(modelArtifacts){
        this.modelArtifacts = modelArtifacts;
    }
Creates an IOHandlerSync that passes saved model artifacts to a callback.

```js
function handleSave(artifacts) {
  // ... do something with the artifacts ...
  return {modelArtifactsInfo: {...}, ...};
}

const saveResult = model.save(tf.io.withSaveHandler(handleSave));
```

@param saveHandler A function that accepts a `ModelArtifacts` and returns a
    `SaveResult`.