@Override
        public void showHeadCharacters() {
            doWithConfig(sourceConfig ->
                    setDataRange(DataRange.fromCharOffset(
                            0,
                            sourceConfig.getMaxCharactersPerFetch())));
        }
Used for navigating standard char based data using char offsets.
stroom-core-client/src/main/java/stroom/data/client/presenter/SourcePresenter.java