private Map<String, Object> getFieldMap(int minSize) {
        if (fields == null) {
            // Compensate for loadfactor and then some, rounded up....
            fields = new LinkedHashMap<>(2 * minSize);
        }
        return fields;
    }
Returns whether any fields are set in this
container-search/src/main/java/com/yahoo/search/result/Hit.java