@Override
    public void onTransactionCompleted(
        long producerId,
        Iterable<TopicPartition> partitions,
        TransactionResult transactionResult
    ) {
        throwIfNotActive();
        throw new IllegalStateException("onTransactionCompleted is not supported.");
    }
See {@link GroupCoordinator#onTransactionCompleted(long, Iterable, TransactionResult)}.
group-coordinator/src/main/java/org/apache/kafka/coordinator/group/GroupCoordinatorService.java