Fix: Thread running at User-initiated quality-of-service for Session replay (#4439)

AVFoundation video maker runs on a lower QoS than user-initiated processes, and the thread sanitizer complains about waiting for it on a higher-level thread. We are changing the QoS of our call to create video.

Author: brustolin

CHANGELOG.md

@@ -19,6 +19,7 @@ via the option `swizzleClassNameExclude`.
 - Finish TTID correctly when viewWillAppear is skipped (#4417)
 - Swizzling RootUIViewController if ignored by `swizzleClassNameExclude` (#4407)
 - Data race in SentrySwizzleInfo.originalCalled (#4434)
+- Thread running at user-initiated quality-of-service for session replay (#4439)
 
 
 ### Improvements

Sources/Sentry/SentrySessionReplayIntegration.m

@@ -281,6 +281,12 @@ - (void)startWithOptions:(SentryReplayOptions *)replayOptions
         = (NSInteger)(shouldReplayFullSession ? replayOptions.sessionSegmentDuration + 1
                                               : replayOptions.errorReplayDuration + 1);
 
+    dispatch_queue_attr_t attributes = dispatch_queue_attr_make_with_qos_class(
+        DISPATCH_QUEUE_SERIAL, DISPATCH_QUEUE_PRIORITY_LOW, 0);
+    SentryDispatchQueueWrapper *dispatchQueue =
+        [[SentryDispatchQueueWrapper alloc] initWithName:"io.sentry.session-replay"
+                                              attributes:attributes];
+
     self.sessionReplay = [[SentrySessionReplay alloc]
         initWithReplayOptions:replayOptions
              replayFolderPath:docs
@@ -290,7 +296,7 @@ - (void)startWithOptions:(SentryReplayOptions *)replayOptions
                  touchTracker:_touchTracker
                  dateProvider:SentryDependencyContainer.sharedInstance.dateProvider
                      delegate:self
-                dispatchQueue:[[SentryDispatchQueueWrapper alloc] init]
+                dispatchQueue:dispatchQueue
            displayLinkWrapper:[[SentryDisplayLinkWrapper alloc] init]];
 
     [self.sessionReplay

Tests/SentryTests/Integrations/SessionReplay/SentrySessionReplayTests.swift

@@ -17,6 +17,8 @@ class SentrySessionReplayTests: XCTestCase {
     private class TestReplayMaker: NSObject, SentryReplayVideoMaker {
         var screens = [String]()
 
+        var createVideoCallBack: ((SentryVideoInfo) -> Void)?
+        
         struct CreateVideoCall {
             var beginning: Date
             var end: Date
@@ -30,6 +32,7 @@ class SentrySessionReplayTests: XCTestCase {
             try? "Video Data".write(to: outputFileURL, atomically: true, encoding: .utf8)
             let videoInfo = SentryVideoInfo(path: outputFileURL, height: 1_024, width: 480, duration: end.timeIntervalSince(beginning), frameCount: 5, frameRate: 1, start: beginning, end: end, fileSize: 10, screens: screens)
 
+            createVideoCallBack?(videoInfo)
             return [videoInfo]
         }
 
@@ -63,7 +66,7 @@ class SentrySessionReplayTests: XCTestCase {
         var lastReplayId: SentryId?
         var currentScreen: String?
 
-        func getSut(options: SentryReplayOptions = .init(sessionSampleRate: 0, onErrorSampleRate: 0) ) -> SentrySessionReplay {
+        func getSut(options: SentryReplayOptions = .init(sessionSampleRate: 0, onErrorSampleRate: 0), dispatchQueue: SentryDispatchQueueWrapper = TestSentryDispatchQueueWrapper() ) -> SentrySessionReplay {
             return SentrySessionReplay(replayOptions: options,
                                        replayFolderPath: cacheFolder,
                                        screenshotProvider: screenshotProvider,
@@ -72,7 +75,7 @@ class SentrySessionReplayTests: XCTestCase {
                                        touchTracker: SentryTouchTracker(dateProvider: dateProvider, scale: 0),
                                        dateProvider: dateProvider,
                                        delegate: self,
-                                       dispatchQueue: TestSentryDispatchQueueWrapper(),
+                                       dispatchQueue: dispatchQueue,
                                        displayLinkWrapper: displayLink)
         }
 
@@ -147,7 +150,7 @@ class SentrySessionReplayTests: XCTestCase {
         XCTAssertNotNil(fixture.lastReplayRecording)
         assertFullSession(sut, expected: true)
     }
-    
+   
     func testReplayScreenNames() throws {
         let fixture = Fixture()
         let sut = fixture.getSut(options: SentryReplayOptions(sessionSampleRate: 1, onErrorSampleRate: 1))