public static DescribeTopicsResult describeTopicsResult(String topic, TopicDescription description) {
        KafkaFutureImpl<TopicDescription> future = new KafkaFutureImpl<>();
        future.complete(description);
        return DescribeTopicsResult.ofTopicNames(Collections.singletonMap(topic, future));
    }
Helper to create a DescribeTopicsResult instance for a given topic.
DescribeTopicsResult's constructor is only accessible from within the
admin package.
clients/src/test/java/org/apache/kafka/clients/admin/AdminClientTestUtils.java