import akka.cluster.ClusterEvent.CurrentClusterState;
import akka.cluster.Member;
import akka.cluster.MemberStatus;
-import com.google.common.base.Optional;
import com.google.common.base.Preconditions;
import com.google.common.base.Stopwatch;
import com.google.common.collect.Sets;
import com.typesafe.config.Config;
import com.typesafe.config.ConfigFactory;
import java.util.List;
+import java.util.Optional;
import java.util.Set;
import java.util.concurrent.TimeUnit;
import org.opendaylight.controller.cluster.access.concepts.MemberName;