public void addReadyBrokersFuture(CompletableFuture<Void> future, int minBrokers) {
        readyBrokersFuture = Optional.of(new ReadyBrokersFuture(future, minBrokers));
        if (readyBrokersFuture.get().check()) {
            readyBrokersFuture.get().future.complete(null);
            readyBrokersFuture = Optional.empty();
        }
    }
Returns true if the broker is active. Active means not fenced nor in controlled
shutdown; Returns false if it is not active or if it does not exist.
metadata/src/main/java/org/apache/kafka/controller/ClusterControlManager.java