Added an async version for AtomicValue and misc javadoc improvements

Change-Id: Idc401964a726d221c01ecda0cc42c4a92551113f
diff --git a/core/api/src/main/java/org/onosproject/store/service/AtomicValueBuilder.java b/core/api/src/main/java/org/onosproject/store/service/AtomicValueBuilder.java
index 3478ce0..d5f226f 100644
--- a/core/api/src/main/java/org/onosproject/store/service/AtomicValueBuilder.java
+++ b/core/api/src/main/java/org/onosproject/store/service/AtomicValueBuilder.java
@@ -68,6 +68,15 @@
     AtomicValueBuilder<V> withMeteringDisabled();
 
     /**
+     * Builds a AsyncAtomicValue based on the configuration options
+     * supplied to this builder.
+     *
+     * @return new AsyncAtomicValue
+     * @throws java.lang.RuntimeException if a mandatory parameter is missing
+     */
+    AsyncAtomicValue<V> buildAsyncValue();
+
+    /**
      * Builds a AtomicValue based on the configuration options
      * supplied to this builder.
      *