Filtering by multivalue date range fields in Solr

See also Filtering by date range with Solr in Drupal 8

If we restrict events to only being one day (no multiday events) which is a request from Cambridge’s Find It staff for both data integrity and service provider user experience reasons (a simpler user interface encouraging proper behavior), this may be more possible, using something like the approach hinted at here:

https://stackoverflow.com/questions/8793316/denormalizing-and-searching-date-ranges-in-solr?rq=1

That is, multivalue dates, rather than multivalue date ranges, may be much more manageable.