public static ApiKeys forId(int id) {
        ApiKeys apiKey = ID_TO_TYPE.get(id);
        if (apiKey == null) {
            throw new IllegalArgumentException("Unexpected api key: " + id);
        }
        return apiKey;
    }
indicates whether the API is enabled for forwarding
clients/src/main/java/org/apache/kafka/common/protocol/ApiKeys.java