import akka.dispatch.OnComplete;
import akka.util.Timeout;
import com.google.common.base.Optional;
import akka.dispatch.OnComplete;
import akka.util.Timeout;
import com.google.common.base.Optional;
import com.google.common.base.Preconditions;
import org.opendaylight.controller.cluster.datastore.identifiers.ShardManagerIdentifier;
import org.opendaylight.controller.cluster.datastore.messages.RegisterChangeListener;
import com.google.common.base.Preconditions;
import org.opendaylight.controller.cluster.datastore.identifiers.ShardManagerIdentifier;
import org.opendaylight.controller.cluster.datastore.messages.RegisterChangeListener;