loosely inspired by the submission of FEP-5bf0 Collection sorting and filtering
## filtering
you could pre-create collections that contain a subset of items, but there's no way to dynamically do server-side filtering; this has to be done client-side by downloading the entire collection and creating any useful indices
## sorting
OrderedCollection is mandated reverse-chronological but it should have been possible to specify the ordering
taking schema.org/ItemList and schema.org/ListItem as prior art:
-`ListItem.position` is the index
-`ItemList.itemListOrder` is the type of ordering
-`itemListOrderAscending`
-`itemListOrderDescending`
-`itemListUnordered`
what might this imply is needed for activitypub?
-`orderedBy`?
- what about multiple ordering criteria? SQL has `ORDER BY`