private void process(@SuppressWarnings("unused") final CommitOnCloseEvent event) {
        if (!requestManagers.commitRequestManager.isPresent())
            return;
        log.debug("Signal CommitRequestManager closing");
        requestManagers.commitRequestManager.get().signalClose();
    }
Process event indicating that the consumer unsubscribed from all topics. This will make
the consumer release its assignment and send a request to leave the group.

@param event Unsubscribe event containing a future that will complete when the callback
             execution for releasing the assignment completes, and the request to leave
             the group is sent out.
clients/src/main/java/org/apache/kafka/clients/consumer/internals/events/ApplicationEventProcessor.java