valueImportanceMap property
A list of values that should be given a different boost when they appear in the result list. For example, if you are boosting a field called "department," query terms that match the department field are boosted in the result. However, you can add entries from the department field to boost documents with those values higher.
For example, you can add entries to the map with names of departments. If you add "HR",5 and "Legal",3 those departments are given special attention when they appear in the metadata of a document. When those terms appear they are given the specified importance instead of the regular importance for the boost.
Implementation
final Map<String, int>? valueImportanceMap;