public Map<Integer, KafkaFuture<Map<String, LogDirDescription>>> descriptions() {
        return futures;
    }
Return a map from brokerId to future which can be used to check the information of partitions on each individual broker.
The result of the future is a map from broker log directory path to a description of that log directory.
clients/src/main/java/org/apache/kafka/clients/admin/DescribeLogDirsResult.java