Various optimisations (#1878)

* Cache TimelineBubbleLayout subview sizes

* Cache MessageText sizes, avoid extra updates

* Only use the `CollapsibleReactionLayout` if there's more than 5 reactions on a particular message

* Upgrade Sentry to 8.13.0, disable various options as they're not useful and impact performance

* Address PR comments, fix unit tests

ElementX/Sources/Other/Extensions/ProposedViewSize.swift

@@ -0,0 +1,24 @@
+//
+// Copyright 2023 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 SwiftUI
+
+extension ProposedViewSize: Hashable {
+    public func hash(into hasher: inout Hasher) {
+        hasher.combine(width)
+        hasher.combine(height)
+    }
+}

ElementX/Sources/Other/Pills/MessageText.swift

@@ -49,7 +49,13 @@ final class MessageTextView: UITextView {
 struct MessageText: UIViewRepresentable {
     @Environment(\.openURL) private var openURLAction: OpenURLAction
     @EnvironmentObject private var viewModel: RoomScreenViewModel.Context
-    @State var attributedString: AttributedString
+    @State private var computedSizes = [Double: CGSize]()
+    
+    @State var attributedString: AttributedString {
+        didSet {
+            computedSizes.removeAll()
+        }
+    }
 
     func makeUIView(context: Context) -> MessageTextView {
         // Need to use TextKit 1 for mentions
@@ -81,13 +87,20 @@ struct MessageText: UIViewRepresentable {
         return textView
     }
 
-    func updateUIView(_ uiView: MessageTextView, context: Context) {
-        uiView.attributedText = NSAttributedString(attributedString)
-        context.coordinator.openURLAction = openURLAction
-    }
+    func updateUIView(_ uiView: MessageTextView, context: Context) { }
 
     func sizeThatFits(_ proposal: ProposedViewSize, uiView: MessageTextView, context: Context) -> CGSize? {
-        uiView.sizeThatFits(CGSize(width: proposal.width ?? UIView.layoutFittingExpandedSize.width, height: UIView.layoutFittingCompressedSize.height))
+        let proposalWidth = proposal.width ?? UIView.layoutFittingExpandedSize.width
+        
+        if let size = computedSizes[proposalWidth] {
+            return size
+        }
+        
+        let size = uiView.sizeThatFits(CGSize(width: proposalWidth, height: UIView.layoutFittingCompressedSize.height))
+        DispatchQueue.main.async {
+            computedSizes[proposalWidth] = size
+        }
+        return size
     }
 
     func makeCoordinator() -> Coordinator {