add comment on setting is loading

Author: samwillis

packages/db/src/query/live/collection-subscriber.ts

@@ -75,6 +75,12 @@ export class CollectionSubscriber<
 
     // Subscribe to subscription status changes to propagate loading state
     const statusUnsubscribe = subscription.on(`status:change`, (event) => {
+      // TODO: For now we are setting this loading state whenever the subscription
+      // status changes to 'loadingMore'. But we have discussed it only happening
+      // when the the live query has it's offset/limit changed, and that triggers the
+      // subscription to request a snapshot. This will require more work to implement,
+      // and builds on https://github.com/TanStack/db/pull/663 which this PR
+      // does not yet depend on.
       if (event.status === `loadingMore`) {
         // Guard against duplicate transitions
         if (!this.subscriptionLoadingPromises.has(subscription)) {