@Override
    public boolean equals(Object obj) {
        if (!(obj instanceof FeatureList)) {
            return false;
        }
        FeatureList lst = (FeatureList)obj;
        if (features.size() != lst.features.size()) {
            return false;
        }
        for (int i = 0; i < features.size(); ++i) {
            if (!features.get(i).equals(lst.features.get(i))) {
                return false;
            }
        }
        return true;
    }
Returns the feature at the given index.

@param i the index of the feature to return.
@return the feature at the given index.
searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/FeatureList.java