@Override
    public CompletableFuture<ReadShareGroupStateResult> readState(ReadShareGroupStateParameters request) {
        GroupTopicPartitionData<PartitionIdLeaderEpochData> reqData = request.groupTopicPartitionData();
        List<TopicData<PartitionAllData>> resultArgs = new ArrayList<>();
        // we will fetch topic and partition info from the request and
        // return valid but default response (keep partition id and topic from request but initialize other
        // values as default).
        for (TopicData<PartitionIdLeaderEpochData> topicData : reqData.topicsData()) {
            resultArgs.add(new TopicData<>(topicData.topicId(), topicData.partitions().stream().
                map(partitionIdData -> PartitionFactory.newPartitionAllData(
                    partitionIdData.partition(), PartitionFactory.DEFAULT_STATE_EPOCH, PartitionFactory.DEFAULT_START_OFFSET, PartitionFactory.DEFAULT_ERROR_CODE, PartitionFactory.DEFAULT_ERR_MESSAGE, Collections.emptyList()))
                .collect(Collectors.toList())));
        }
        return CompletableFuture.completedFuture(new ReadShareGroupStateResult.Builder().setTopicsData(resultArgs).build());
    }
A no-op singleton implementation of {@link Persister} interface.
server-common/src/main/java/org/apache/kafka/server/group/share/NoOpShareStatePersister.java