Enhancement: Use compute to offload heavy work from the main thread

CHANGELOG.md

@@ -3,6 +3,7 @@
 * Add `SentryAssetBundle` for automatic spans for asset loading (#685)
 * Feat: Configure idle transaction duration (#705)
 * Fix: `maxRequestBodySize` should be `never` by default when using the FailedRequestClientAdapter directly (#701)
+* Enhancement: Use compute to offload heavy work from the main thread (#)
 
 # 6.3.0-beta.2
 
@@ -12,7 +13,7 @@
 
 # 6.3.0-beta.1
 
-* Enha: Replace flutter default root name '/' with 'root' (#678)
+* Enhancement: Replace flutter default root name '/' with 'root' (#678)
 * Fix: Use 'navigation' instead of 'ui.load' for auto transaction operation (#675)
 * Fix: Use correct data/extras type in tracer (#693)
 * Fix: Do not throw when Throwable type is not supported for associating errors to a transaction (#692)

flutter/lib/src/file_system_transport.dart

@@ -1,5 +1,6 @@
 import 'dart:typed_data';
 
+import 'package:flutter/foundation.dart';
 import 'package:flutter/services.dart';
 import 'package:sentry/sentry.dart';
 
@@ -11,12 +12,14 @@ class FileSystemTransport implements Transport {
 
   @override
   Future<SentryId?> send(SentryEnvelope envelope) async {
-    final envelopeData = <int>[];
-    await envelope.envelopeStream(_options).forEach(envelopeData.addAll);
-    // https://flutter.dev/docs/development/platform-integration/platform-channels#codec
-    final args = [Uint8List.fromList(envelopeData)];
+    final eventIdLabel = envelope.header.eventId?.toString() ?? '';
+    final args = await compute(
+      _convert,
+      _CaptureEnvelopeData(envelope, _options),
+      debugLabel: 'captureEnvelope $eventIdLabel',
+    );
     try {
-      await _channel.invokeMethod<void>('captureEnvelope', args);
+      await _channel.invokeMethod<void>('captureEnvelope', [args]);
     } catch (exception, stackTrace) {
       _options.logger(
         SentryLevel.error,
@@ -30,3 +33,19 @@ class FileSystemTransport implements Transport {
     return envelope.header.eventId;
   }
 }
+
+class _CaptureEnvelopeData {
+  SentryEnvelope envelope;
+  SentryOptions options;
+
+  _CaptureEnvelopeData(this.envelope, this.options);
+}
+
+Future<Uint8List> _convert(
+  _CaptureEnvelopeData data,
+) async {
+  final envelopeData = <int>[];
+  await data.envelope.envelopeStream(data.options).forEach(envelopeData.addAll);
+  // https://flutter.dev/docs/development/platform-integration/platform-channels#codec
+  return Uint8List.fromList(envelopeData);
+}