Pagination, WebSockets, and Coordinated Refresh in Kotlin Multiplatform

Part 4 of 4 — The final part of this series. Parts 1 , 2 , and 3 cover the Ktor client setup, error-handling layer, and RequestState pattern that this part extends. The first three parts built the foundation — a configured Ktor client, a typed error-handling layer, and a state management pattern that carries data cleanly from repository to UI. For a large class of screens, that's everything you need. But some screens need more. A feed that loads pages of data as the user scrolls. A chat screen that receives real-time messages over a WebSocket connection while simultaneously loading paginated history. A screen that refreshes six independent data sources at once and needs to wait for all of them before hiding the pull-to-refresh indicator. These aren't edge cases — they're common in any serious mobile app. And the good news is that none of them require new primitives. They all extend the same architecture you've already seen. This part covers GenericPagingSource for pagination, PagingSta