func list(client *pubsub.Client) ([]*pubsub.Subscription, error) {
	ctx := context.Background()
	// [START get_all_subscriptions]
	var subs []*pubsub.Subscription
	it := client.Subscriptions(ctx)
	for {
		s, err := it.Next()
		if err == iterator.Done {
			break
		}
		if err != nil {
			return nil, err
		}
		subs = append(subs, s)
	}
	// [END get_all_subscriptions]
	return subs, nil
}