public void forEachFieldAsRaw(RawUtf8Consumer consumer) {
        if (fields == null) return;
        fields.forEach(consumer);
    }
Receive a callback on the given object for each field in this hit,
where the callback will provide raw utf-8 byte data for strings whose data
is already available at this form.
This is the most resource efficient way of traversing all the fields of a hit
in renderers which produces utf-8.
container-search/src/main/java/com/yahoo/search/result/Hit.java