public static DescribeTopicsResult describeTopicsResult(Map<String, TopicDescription> topicDescriptions) {
        return DescribeTopicsResult.ofTopicNames(topicDescriptions.entrySet().stream()
                .collect(Collectors.toMap(Map.Entry::getKey, e -> KafkaFuture.completedFuture(e.getValue()))));
    }
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