perf: add RepaintBoundary around chat messages

Wrap each Message widget in a RepaintBoundary to isolate repaints per
message. Without this, a state change on a single message (hover,
reaction update) could trigger a repaint of the entire visible chat
area due to ~12 levels of widget nesting without isolation.

The memory cost is bounded because SliverChildBuilderDelegate only
builds the ~10-15 messages currently visible on screen.

Also remove a redundant dart:typed_data import in
hive_collections_database.dart that was failing CI analyze.

Author: Clement Guyon

lib/pages/chat/chat_event_list_item.dart

@@ -34,75 +34,78 @@ class ChatEventListItem extends StatelessWidget {
       index: index,
       controller: controller.scrollController,
       highlightColor: Theme.of(context).highlightColor,
-      child: Message(
-        key: GlobalObjectKey(event.eventId),
-        event,
-        matrixState: controller.matrix!,
-        onSwipe: (direction) => controller.replyAction(replyTo: event),
-        onAvatarTap: (Event event) => controller.onContactTap(
-          contactPresentationSearch: event.senderFromMemoryOrFallback
-              .toContactPresentationSearch(),
-          context: context,
-          path: 'rooms',
-        ),
-        onSelect: controller.onSelectMessage,
-        selectMode: controller.selectMode,
-        maxWidth: constraints.maxWidth,
-        scrollToEventId: (String eventId) =>
-            controller.scrollToEventId(eventId, highlight: true),
-        selected: controller.selectedEvents.any(
-          (e) => e.eventId == event.eventId,
-        ),
-        timeline: controller.timeline!,
-        previousEvent: previousEvent,
-        nextEvent: nextEvent,
-        onHover: (isHover, event) => controller.onHover(isHover, index, event),
-        isHoverNotifier: controller.focusHover,
-        listHorizontalActionMenu: controller.listHorizontalActionMenuBuilder(
+      child: RepaintBoundary(
+        child: Message(
+          key: GlobalObjectKey(event.eventId),
           event,
+          matrixState: controller.matrix!,
+          onSwipe: (direction) => controller.replyAction(replyTo: event),
+          onAvatarTap: (Event event) => controller.onContactTap(
+            contactPresentationSearch: event.senderFromMemoryOrFallback
+                .toContactPresentationSearch(),
+            context: context,
+            path: 'rooms',
+          ),
+          onSelect: controller.onSelectMessage,
+          selectMode: controller.selectMode,
+          maxWidth: constraints.maxWidth,
+          scrollToEventId: (String eventId) =>
+              controller.scrollToEventId(eventId, highlight: true),
+          selected: controller.selectedEvents.any(
+            (e) => e.eventId == event.eventId,
+          ),
+          timeline: controller.timeline!,
+          previousEvent: previousEvent,
+          nextEvent: nextEvent,
+          onHover: (isHover, event) =>
+              controller.onHover(isHover, index, event),
+          isHoverNotifier: controller.focusHover,
+          listHorizontalActionMenu: controller.listHorizontalActionMenuBuilder(
+            event,
+          ),
+          onMenuAction: controller.handleHorizontalActionMenu,
+          hideKeyboardChatScreen: controller.onHideKeyboardAndEmoji,
+          markedUnreadLocation: controller.unreadReceivedMessageLocation,
+          timestampCallback: (event) {
+            controller.handleDisplayStickyTimestamp(event.originServerTs);
+          },
+          onEventVisible: controller.onEventVisible,
+          onDisplayEmojiReaction: controller.onDisplayEmojiReaction,
+          onHideEmojiReaction: controller.onHideEmojiReaction,
+          listAction: controller.listHorizontalActionMenuBuilder(event).map((
+            action,
+          ) {
+            return ContextMenuAction(name: action.action.name);
+          }).toList(),
+          onPickEmojiReaction: () {},
+          onSelectEmojiReaction: (emoji, event) {
+            controller.sendEmojiAction(emoji: emoji, event: event);
+          },
+          onForward: (event) {
+            controller.forwardEventsAction(event: event);
+          },
+          onReply: (event) {
+            controller.replyAction(replyTo: event);
+          },
+          onCopy: controller.copyEventsAction,
+          onPin: (event) {
+            controller.pinEventAction(event);
+          },
+          onSaveToDownload: (event) =>
+              controller.saveSelectedEventToDownloadAndroid(context, event),
+          onSaveToGallery: (event) =>
+              controller.saveSelectedEventToGallery(context, event),
+          onTapMoreButton: controller.handleOnTapMoreButtonOnWeb,
+          onEdit: (event) {
+            controller.editAction(editEvent: event);
+          },
+          onDelete: (context, event) {
+            controller.deleteEventAction(context, event);
+          },
+          recentEmojiFuture: controller.getRecentReactionsInteractor.execute(),
+          onReport: controller.reportEventAction,
+          onRetryTextMessage: controller.retryTextMessage,
         ),
-        onMenuAction: controller.handleHorizontalActionMenu,
-        hideKeyboardChatScreen: controller.onHideKeyboardAndEmoji,
-        markedUnreadLocation: controller.unreadReceivedMessageLocation,
-        timestampCallback: (event) {
-          controller.handleDisplayStickyTimestamp(event.originServerTs);
-        },
-        onEventVisible: controller.onEventVisible,
-        onDisplayEmojiReaction: controller.onDisplayEmojiReaction,
-        onHideEmojiReaction: controller.onHideEmojiReaction,
-        listAction: controller.listHorizontalActionMenuBuilder(event).map((
-          action,
-        ) {
-          return ContextMenuAction(name: action.action.name);
-        }).toList(),
-        onPickEmojiReaction: () {},
-        onSelectEmojiReaction: (emoji, event) {
-          controller.sendEmojiAction(emoji: emoji, event: event);
-        },
-        onForward: (event) {
-          controller.forwardEventsAction(event: event);
-        },
-        onReply: (event) {
-          controller.replyAction(replyTo: event);
-        },
-        onCopy: controller.copyEventsAction,
-        onPin: (event) {
-          controller.pinEventAction(event);
-        },
-        onSaveToDownload: (event) =>
-            controller.saveSelectedEventToDownloadAndroid(context, event),
-        onSaveToGallery: (event) =>
-            controller.saveSelectedEventToGallery(context, event),
-        onTapMoreButton: controller.handleOnTapMoreButtonOnWeb,
-        onEdit: (event) {
-          controller.editAction(editEvent: event);
-        },
-        onDelete: (context, event) {
-          controller.deleteEventAction(context, event);
-        },
-        recentEmojiFuture: controller.getRecentReactionsInteractor.execute(),
-        onReport: controller.reportEventAction,
-        onRetryTextMessage: controller.retryTextMessage,
       ),
     );
   }

lib/utils/matrix_sdk_extensions/hive_collections_database.dart

@@ -21,7 +21,6 @@
 import 'dart:async';
 import 'dart:convert';
 import 'dart:math';
-import 'dart:typed_data';
 
 import 'package:flutter/foundation.dart';