IsUndelivered() returns false even when event was not delivered

[dennisjac]

I just adapted the sender and receiver examples from the main repo page a little bit and when the receiver isn't running but I run the sender then IsUndelivered() returns false even though the event was not delivered.

	event := cloudevents.NewEvent()
	event.SetSource("example.com/test")
	event.SetType("example.type")
	event.SetData(cloudevents.ApplicationJSON, data)
	ctx := cloudevents.ContextWithTarget(context.Background(), "http://127.0.0.1:8080/")
	result := c.Send(ctx, event)
	log.Printf("IsUndelivered(result): %+v\n", cloudevents.IsUndelivered(result))
	if cloudevents.IsUndelivered(result) {
		log.Fatalf("undelivered: %+v\n", result)
	}
	fmt.Printf("delivered: %+v\n", result)

results in:

delivered: Post "http://127.0.0.1:8080/": dial tcp 127.0.0.1:8080: connect: connection refused
2022/10/27 22:06:37 IsUndelivered(result): false

IsUndelivered() should clearly return true in this case.