public CompletableFuture<MigrationDriverState> migrationState() {
        CompletableFuture<MigrationDriverState> stateFuture = new CompletableFuture<>();
        eventQueue.append(() -> stateFuture.complete(migrationState));
        return stateFuture;
    }
A callback for when the migration state has been recovered from ZK. This is used to delay the installation of this
MetadataPublisher with MetadataLoader.
metadata/src/main/java/org/apache/kafka/metadata/migration/KRaftMigrationDriver.java