public Object get(String key) {
        if (map!=null) return map.get(key);
        if (unmodifiableMap!=null) return unmodifiableMap.get(key);
        return null;
    }
Deep clones a map - this handles all value types which can be found in a query profile
container-search/src/main/java/com/yahoo/search/query/profile/CopyOnWriteContent.java