public KafkaFuture<Void> all() {
        return (topicIdFutures == null) ? KafkaFuture.allOf(nameFutures.values().toArray(new KafkaFuture[0])) :
            KafkaFuture.allOf(topicIdFutures.values().toArray(new KafkaFuture[0]));
    }
@return a future which succeeds only if all the topic deletions succeed.
clients/src/main/java/org/apache/kafka/clients/admin/DeleteTopicsResult.java