Need to preserve attachment source location info

Sources/Testing/ABI/Encoded/ABI.EncodedAttachment.swift

@@ -60,6 +60,12 @@ extension ABI {
     /// - Warning: Inline attachment content is not yet part of the JSON schema.
     var _bytes: Bytes?
 
+    /// The source location where this attachment was created.
+    ///
+    /// - Warning: Attachment source locations are not yet part of the JSON
+    ///   schema.
+    var _sourceLocation: SourceLocation?
+
     init(encoding attachment: borrowing Attachment<AnyAttachable>, in eventContext: borrowing Event.Context) {
       path = attachment.fileSystemPath
       _preferredName = attachment.preferredName
@@ -73,6 +79,8 @@ extension ABI {
           return nil
         }
       }
+
+      _sourceLocation = attachment.sourceLocation
     }
 
     /// A structure representing the bytes of an attachment.

Sources/Testing/Events/Event.swift

@@ -289,7 +289,7 @@ extension Event {
       Issue(event)?.record()
     case .valueAttached:
       if let attachment = event.attachment {
-        Attachment.record(attachment)
+        Attachment.record(attachment, sourceLocation: attachment._sourceLocation ?? .__here())
       }
     default:
       // Not handled here.

Tests/TestingTests/EventTests.swift

@@ -182,6 +182,7 @@ private func MockXCTAttachmentAdd(_ string: String, named name: String) {
   }
 
   @Test func `Attachment is passed to fallback event handler`() async {
+    MockXCTAttachmentAdd("0123456789", named: "numbers.txt")
     await confirmation("Attachment recorded") { valueAttached in
       var configuration = Configuration()
       configuration.eventHandler = { event, _ in