Paginate data with query cursors

[mnightingale]

As I understand it currently queries don't really paginate, the query limit is just continuously increased and any duplicate ids are ignored.
i.e. it queries for 20 items, then 40, 60, 80, etc.
In some cases this can cause a lot of document reads.

Would a PR be welcome that uses the firestore pagination methods Paginate data with query cursors ?

I don't think this would cause an issue, startAt requires a orderBy but so does limit.

I was thinking something like:

stepLimit + 1 because I choose to use startAt rather than startAfter in case there are multiple items with the same order key and I want stepLimit extra items.

let queryLimited = ref.current

if (after !== null) {
  queryLimited = queryLimited.startAt(after).limit(stepLimit + 1)
} else {
  queryLimited = queryLimited.limit(stepLimit)
}