Hide public timeline description when user begins scrolling rather than

after cell moves offscreen

Fixes description getting dismissed prematurely on iOS 14 and hitching
when the cell moves offscreen

Tusker/Screens/Timeline/TimelineTableViewController.swift

@@ -252,18 +252,13 @@ class TimelineTableViewController: DiffableTimelineLikeTableViewController<Timel
         }
     }
     
-    override func tableView(_ tableView: UITableView, didEndDisplaying cell: UITableViewCell, forRowAt indexPath: IndexPath) {
-        if let item = dataSource.itemIdentifier(for: indexPath),
-           case .publicTimelineDescription(local: _) = item {
-            // trying to remove cells right in didEndDisplaying crashes in UIKit
-            DispatchQueue.main.async {
-                    self.tableView.contentOffset.y -= cell.bounds.height
-                
-                var snapshot = self.dataSource.snapshot()
-                snapshot.deleteItems([item])
-                self.dataSource.apply(snapshot) {
-                }
-            }
+    override func scrollViewWillBeginDragging(_ scrollView: UIScrollView) {
+        super.scrollViewWillBeginDragging(scrollView)
+        
+        if isShowingTimelineDescription {
+            var snapshot = self.dataSource.snapshot()
+            snapshot.deleteSections([.header])
+            self.dataSource.apply(snapshot, animatingDifferences: true)
         }
     }
     

Tusker/Screens/Utilities/DiffableTimelineLikeTableViewController.swift

@@ -117,6 +117,7 @@ class DiffableTimelineLikeTableViewController<Section: Hashable & CaseIterable,
                 case let .success(snapshot):
                     self.dataSource.apply(snapshot, animatingDifferences: false)
                     self.state = .loaded
+                    
                 case let .failure(.client(error)):
                     self.state = .unloaded
                     var config = ToastConfiguration(title: "Error Loading")