fix(unity): update SentryEvent to have IsCaptured to allow dropping screenshots of filtered events (#5162)

* Update SentryEvent to have WasCaptured on Unity

* Format code

* apply suggestions from code review

---------

Co-authored-by: Sentry Github Bot <bot+github-bot@sentry.io>

Author: JoshuaMoelans

src/Sentry/Platforms/Unity/SentryEvent.Unity.cs

@@ -0,0 +1,15 @@
+#if SENTRY_UNITY
+
+namespace Sentry;
+
+public sealed partial class SentryEvent
+{
+    /// <summary>
+    /// Indicates whether this event was actually captured and sent to Sentry.
+    /// Used by the Unity SDK's async screenshot capture to avoid sending orphaned attachments.
+    /// Defaults to false (safe: if unset, attachments are skipped rather than orphaned).
+    /// </summary>
+    internal bool IsCaptured { get; set; }
+}
+
+#endif

src/Sentry/SentryClient.cs

@@ -411,7 +411,14 @@ private SentryId DoSendEvent(SentryEvent @event, SentryHint? hint, Scope? scope)
 
         var attachments = hint.Attachments.ToList();
         var envelope = Envelope.FromEvent(processedEvent, _options.DiagnosticLogger, attachments, scope.SessionUpdate);
-        return CaptureEnvelope(envelope) ? processedEvent.EventId : SentryId.Empty;
+        if (CaptureEnvelope(envelope))
+        {
+#if SENTRY_UNITY
+            @event.IsCaptured = true; // See SentryEvent.Unity.cs for more details.
+#endif
+            return processedEvent.EventId;
+        }
+        return SentryId.Empty;
     }
 
     private IReadOnlyCollection<Exception>? ApplyExceptionFilters(Exception? exception)

src/Sentry/SentryEvent.cs

@@ -10,7 +10,7 @@ namespace Sentry;
 /// </summary>
 /// <seealso href="https://develop.sentry.dev/sdk/event-payloads/" />
 [DebuggerDisplay("{GetType().Name,nq}: {" + nameof(EventId) + ",nq}")]
-public sealed class SentryEvent : IEventLike, ISentryJsonSerializable
+public sealed partial class SentryEvent : IEventLike, ISentryJsonSerializable
 {
     private IDictionary<string, string>? _modules;