@Override
    public String toString() {
        return "ListConsumerGroupOffsetsSpec(" +
                "topicPartitions=" + topicPartitions +
                ')';
    }
Returns the topic partitions whose offsets are to be listed for a consumer group.
{@code null} indicates that offsets of all partitions of the group are to be listed.
clients/src/main/java/org/apache/kafka/clients/admin/ListConsumerGroupOffsetsSpec.java