Implement event-based streaming iterator for ConsistentMultimap primitive

Change-Id: I4f41876f91ec752cb3d6ac0fd352ff6e8798dfd6
diff --git a/core/api/src/test/java/org/onosproject/store/service/TestConsistentMultimap.java b/core/api/src/test/java/org/onosproject/store/service/TestConsistentMultimap.java
index 099758b..a97337e 100644
--- a/core/api/src/test/java/org/onosproject/store/service/TestConsistentMultimap.java
+++ b/core/api/src/test/java/org/onosproject/store/service/TestConsistentMultimap.java
@@ -19,6 +19,7 @@
 import com.google.common.collect.Multiset;
 
 import java.util.Collection;
+import java.util.Iterator;
 import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.Executor;
@@ -130,6 +131,11 @@
     }
 
     @Override
+    public Iterator<Map.Entry<K, V>> iterator() {
+        return null;
+    }
+
+    @Override
     public Map<K, Collection<V>> asMap() {
         return null;
     }