public static DeleteTopicsResult deleteTopicsResult(String topic, Throwable t) {
        KafkaFutureImpl<Void> future = new KafkaFutureImpl<>();
        future.completeExceptionally(t);
        return DeleteTopicsResult.ofTopicNames(Collections.singletonMap(topic, future));
    }
Helper to create a DeleteTopicsResult instance for a given Throwable.
DeleteTopicsResult's constructor is only accessible from within the
admin package.
clients/src/test/java/org/apache/kafka/clients/admin/AdminClientTestUtils.java