private Inspector getInspector(String featureName) {
        Inspector featureValue = encodedValues.field(featureName);
        if (featureValue.valid()) return featureValue;

        // Try to wrap by rankingExpression(name)
        return encodedValues.field(wrapInRankingExpression(featureName));
    }
Sets a new or modified value in this.
container-search/src/main/java/com/yahoo/search/result/FeatureData.java