Set visible ranges on the home screen sliding sync view (#342)

* Set visible ranges on the home screen sliding sync view
* Prevent the visible items from being updated while in search mode
* Enable diffs on invalidations as they seem to fix duplicated events in the home screen room list
* Promoted some diffing logs to info from verbose

ElementX/Sources/Other/ScrollViewAdapter.swift

@@ -0,0 +1,54 @@
+//
+// Copyright 2022 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import Combine
+import UIKit
+
+class ScrollViewAdapter: NSObject, UIScrollViewDelegate {
+    var scrollView: UIScrollView? {
+        didSet {
+            oldValue?.delegate = nil
+            scrollView?.delegate = self
+        }
+    }
+        
+    var isScrolling = PassthroughSubject<Bool, Never>()
+        
+    private func update() {
+        guard let scrollView else { return }
+        isScrolling.send(scrollView.isDragging || scrollView.isDecelerating)
+    }
+    
+    func scrollViewWillBeginDragging(_ scrollView: UIScrollView) {
+        update()
+    }
+    
+    func scrollViewDidEndDragging(_ scrollView: UIScrollView, willDecelerate decelerate: Bool) {
+        update()
+    }
+    
+    func scrollViewDidEndScrollingAnimation(_ scrollView: UIScrollView) {
+        update()
+    }
+        
+    func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {
+        update()
+    }
+    
+    func scrollViewDidScrollToTop(_ scrollView: UIScrollView) {
+        update()
+    }
+}