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