HOTFIX: Fix optional import in ConsumerCoordinator
This was caused by back-to-back merging of (which removed the Optional import) and (which needed the import).
Reviewers: Jason Gustafson
@@ -64,6 +64,7 @@ import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Objects;
+import java.util.Optional;
import java.util.Set;
import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.concurrent.atomic.AtomicBoolean;
