Added DistributedPrimitive interface
Added AsyncDistributedSet that provides async set operations

Change-Id: I83494075a7973694ea6b7445ff4799b7a1a50641
diff --git a/core/api/src/main/java/org/onosproject/store/service/DistributedQueue.java b/core/api/src/main/java/org/onosproject/store/service/DistributedQueue.java
index cc0b00d..777152c 100644
--- a/core/api/src/main/java/org/onosproject/store/service/DistributedQueue.java
+++ b/core/api/src/main/java/org/onosproject/store/service/DistributedQueue.java
@@ -24,7 +24,7 @@
  *
  * @param <E> queue entry type
  */
-public interface DistributedQueue<E> {
+public interface DistributedQueue<E> extends DistributedPrimitive {
 
     /**
      * Returns total number of entries in the queue.