Make wasDeferred DEBUG-only

Author: grynspan

Sources/Testing/Events/Event.swift

@@ -191,13 +191,15 @@ public struct Event: Sendable {
   /// The instant at which the event occurred.
   public var instant: Test.Clock.Instant
 
+#if DEBUG
   /// Whether or not this event was deferred.
   ///
   /// A deferred event is handled significantly later than when was posted.
   ///
   /// We currently use this property in our tests, but do not expose it as API
   /// or SPI. We can expose it in the future if tools need it.
   var wasDeferred: Bool = false
+#endif
 
   /// Initialize an instance of this type.
   ///

Sources/Testing/Traits/AttachmentSavingTrait.swift

@@ -200,8 +200,11 @@ extension AttachmentSavingTrait: TestScoping {
 
       // Finally issue the attachment-recorded events that we deferred.
       let eventContext = Event.Context(test: test, testCase: testCase, configuration: configuration)
-      for var event in context.deferredEvents {
+      for event in context.deferredEvents {
+#if DEBUG
+        var event = event
         event.wasDeferred = true
+#endif
         configuration.eventHandler(event, eventContext)
       }
     }

Tests/TestingTests/Traits/AttachmentSavingTraitTests.swift

@@ -23,9 +23,11 @@ struct `AttachmentSavingTrait tests` {
             case .issueRecorded:
               issueRecorded()
             case let .valueAttached(attachment):
+#if DEBUG
               if trait != nil {
                 #expect(event.wasDeferred)
               }
+#endif
               if let expectedPreferredName {
                 #expect(attachment.preferredName == expectedPreferredName)
               }