private List<KafkaServer> brokers() {
        final List<KafkaServer> servers = new ArrayList<>();
        for (final KafkaEmbedded broker : brokers) {
            servers.add(broker.kafkaServer());
        }
        return servers;
    }
Deletes all topics and blocks until all topics got deleted.

@param timeoutMs the max time to wait for the topics to be deleted (does not block if {@code <= 0})
streams/src/test/java/org/apache/kafka/streams/integration/utils/EmbeddedKafkaCluster.java