@Override
    public int hashCode() {
        return stringValue.hashCode();
    }
Perform the substitution in this, by looking up in the given properties,
and returns the resulting string

@param context the content which is used to resolve profile variants when looking up substitution values
@param substitution the properties in which values to be substituted are looked up
container-search/src/main/java/com/yahoo/search/query/profile/SubstituteString.java