Sketching more topology related stuff.
diff --git a/net/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleTopologyManager.java b/net/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleTopologyManager.java
index 1ea0638..1e95598 100644
--- a/net/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleTopologyManager.java
+++ b/net/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleTopologyManager.java
@@ -53,6 +53,8 @@
     private final AbstractListenerRegistry<TopologyEvent, TopologyListener>
             listenerRegistry = new AbstractListenerRegistry<>();
 
+    private final SimpleTopologyStore store = new SimpleTopologyStore();
+
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
     private EventDeliveryService eventDispatcher;