Include mutation's version in Iterator::operator*

include/VersionedMap.h

@@ -104,9 +104,13 @@ struct VersionedMap {
     Iterator(Iterator &&) noexcept;
     Iterator &operator=(Iterator &&) noexcept;
 
+    struct VersionedMutation : Mutation {
+      int64_t version;
+    };
+
     /** iter must not be `end()`. Memory pointed-to by return value is valid as
      * long as the iterator is valid. */
-    Mutation operator*() const;
+    VersionedMutation operator*() const;
 
     /** iter must not be `end()` */
     Iterator &operator++();