At its default/simplest form, values - one per doc - are used as the score of that doc. ///
Values are instantiated as /// {@link Lucene.Net.Search.Function.DocValues DocValues} for a particular reader. ///
ValueSource implementations differ in RAM requirements: it would always be a factor /// of the number of documents, but for each document the number of bytes can be 1, 2, 4, or 8. /// ///
/// WARNING: The status of the search.function package is experimental. /// The APIs introduced here might change in the future and will not be /// supported anymore in such a case. /// /// ///