improve timestamps

Author: vaind

flutter/lib/src/event_processor/screenshot_event_processor.dart

@@ -125,6 +125,6 @@ class ScreenshotEventProcessor implements EventProcessor {
   }
 
   @internal
-  Future<Uint8List?> createScreenshot() => _recorder
-      .capture((ScreenshotPng screenshot) => Future.value(screenshot.data));
+  Future<Uint8List?> createScreenshot() =>
+      _recorder.capture((screenshot) => Future.value(screenshot.data));
 }

flutter/lib/src/screenshot/recorder.dart

@@ -60,9 +60,10 @@ class ScreenshotRecorder {
   /// To prevent accidental addition of await before that happens,
   ///
   /// THIS FUNCTION MUST NOT BE ASYNC.
-  Future<R> capture<R>(Future<R> Function(ScreenshotPng) callback) {
+  Future<R> capture<R>(Future<R> Function(ScreenshotPng) callback,
+      [Flow? flow]) {
     try {
-      final flow = Flow.begin();
+      flow ??= Flow.begin();
       Timeline.startSync('Sentry::captureScreenshot', flow: flow);
       final context = sentryScreenshotWidgetGlobalKey.currentContext;
       final renderObject =
@@ -213,7 +214,7 @@ class _Capture<R> {
           final imageData =
               await finalImage.toByteData(format: ImageByteFormat.png);
           final png = ScreenshotPng(finalImage.width, finalImage.height,
-              imageData!.buffer.asUint8List(), timestamp);
+              imageData!.buffer.asUint8List(), timestamp, flow);
           Timeline.finishSync(); // Sentry::screenshotToPng
 
           Timeline.startSync('Sentry::screenshotCallback', flow: flow);
@@ -310,8 +311,10 @@ class ScreenshotPng {
   final int height;
   final Uint8List data;
   final DateTime timestamp;
+  final Flow flow;
 
-  const ScreenshotPng(this.width, this.height, this.data, this.timestamp);
+  const ScreenshotPng(
+      this.width, this.height, this.data, this.timestamp, this.flow);
 
   bool hasSameImageAs(ScreenshotPng other) {
     if (other.width != width || other.height != height) {

flutter/lib/src/screenshot/retrier.dart

@@ -52,13 +52,24 @@ class ScreenshotRetrier<R> {
     final prevScreenshot = _previousScreenshot;
     _previousScreenshot = screenshot;
     if (prevScreenshot != null && prevScreenshot.hasSameImageAs(screenshot)) {
+      // Sucessfully captured a stable screenshot (repeated at least twice).
       _tries = 0;
-      await _callback(screenshot);
+      if (prevScreenshot.flow.id == screenshot.flow.id) {
+        // If it's from the same (retry) flow, use the first screenshot timestamp.
+        await _callback(prevScreenshot);
+      } else {
+        // Otherwise this was called from a scheduler (in a new flow) so use
+        // the new timestamp.
+        await _callback(screenshot);
+      }
     } else if (_tries > _options.screenshotRetries) {
       throw Exception('Failed to capture a stable screenshot. '
           'Giving up after $_tries tries.');
     } else {
-      ensureFrameAndAddCallback(capture);
+      ensureFrameAndAddCallback((Duration sinceSchedulerEpoch) {
+        _tries++;
+        _recorder.capture(_onImageCaptured, screenshot.flow);
+      });
     }
   }
 }