private RequestFuture<Void> sendFindCoordinatorRequest(Node node) {
        log.debug("Sending FindCoordinator request to broker {}", node);
        FindCoordinatorRequestData data = new FindCoordinatorRequestData()
                .setKeyType(CoordinatorType.GROUP.id())
                .setKey(this.rebalanceConfig.groupId);
        FindCoordinatorRequest.Builder requestBuilder = new FindCoordinatorRequest.Builder(data);
        return client.send(node, requestBuilder)
                .compose(new FindCoordinatorResponseHandler());
    }
Discover the current coordinator for the group. Sends a FindCoordinator request to
the given broker node. The returned future should be polled to get the result of the request.
@return A request future which indicates the completion of the metadata request
clients/src/main/java/org/apache/kafka/clients/consumer/internals/AbstractCoordinator.java