Fixes "Failed to persist session" error on iOS (#3655)

Author: jamescrosswell

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+### Fixes
+
+- Fixed "Failed to persist session" error on iOS ([#3655](https://github.com/getsentry/sentry-dotnet/pull/3655))
+
 ### Dependencies
 
 - Bump CLI from v2.36.5 to v2.36.6 ([#3647](https://github.com/getsentry/sentry-dotnet/pull/3647))

src/Sentry/GlobalSessionManager.cs

@@ -76,10 +76,9 @@ private void PersistSession(SessionUpdate update, DateTimeOffset? pauseTimestamp
                 return;
             }
 
-            using var writer = new Utf8JsonWriter(file);
-
             try
             {
+                using var writer = new Utf8JsonWriter(file);
                 persistedSessionUpdate.WriteTo(writer, _options.DiagnosticLogger);
                 writer.Flush();
             }