public Map<String, Map<String, Short>> toMap() {
        return features.entrySet().stream().collect(
            Collectors.toMap(
                Map.Entry::getKey,
                entry -> entry.getValue().toMap()));
    }
@return   A map representation of the underlying features. The returned value can be converted
          back to Features using one of the from*FeaturesMap() APIs of this class.
clients/src/main/java/org/apache/kafka/common/feature/Features.java