public KafkaFuture<Map<String, ConsumerGroupDescription>> all() {
        return KafkaFuture.allOf(futures.values().toArray(new KafkaFuture[0])).thenApply(
            nil -> {
                Map<String, ConsumerGroupDescription> descriptions = new HashMap<>(futures.size());
                futures.forEach((key, future) -> {
                    try {
                        descriptions.put(key, future.get());
                    } catch (InterruptedException | ExecutionException e) {
                        // This should be unreachable, since the KafkaFuture#allOf already ensured
                        // that all of the futures completed successfully.
                        throw new RuntimeException(e);
                    }
                });
                return descriptions;
            });
    }
Return a future which yields all ConsumerGroupDescription objects, if all the describes succeed.
clients/src/main/java/org/apache/kafka/clients/admin/DescribeConsumerGroupsResult.java