class BrokerInterceptor implements Interceptor {

    @Override
    public void notifyTopicUnsubscribed(final String topic, final String clientID, final String username) {
        for (final InterceptHandler handler : this.handlers.get(InterceptUnsubscribeMessage.class)) {
            LOG.debug("Notifying MQTT UNSUBSCRIBE message to interceptor. CId={}, topic={}, interceptorId={}", clientID,
                topic, handler.getID());
            executor.execute(() -> handler.onUnsubscribe(new InterceptUnsubscribeMessage(topic, clientID, username)));
        }
    }

    private  BrokerInterceptor(int poolSize, List<InterceptHandler> handlers);
      BrokerInterceptor(List<InterceptHandler> handlers);
      BrokerInterceptor(IConfig props, List<InterceptHandler> handlers);

}