import com.google.common.base.Optional;
import com.google.common.base.Preconditions;
import org.opendaylight.controller.cluster.common.actor.AbstractUntypedActorWithMetering;
-import org.opendaylight.controller.cluster.datastore.TransactionProxy.TransactionType;
import org.opendaylight.controller.cluster.datastore.exceptions.UnknownMessageException;
import org.opendaylight.controller.cluster.datastore.jmx.mbeans.shard.ShardStats;
import org.opendaylight.controller.cluster.datastore.messages.CloseTransaction;