@Override
        public FieldValue clone() {
            try {
                FieldValue clone = (FieldValue)super.clone();
                clone.value = QueryProfile.cloneIfNecessary(this.value);
                return clone;
            }
            catch (CloneNotSupportedException e) {
                throw new RuntimeException(e);
            }
        }
Clone by filling in the value from the given variants
container-search/src/main/java/com/yahoo/search/query/profile/QueryProfileVariants.java