// as it preserves the previous behavior, but allows components to opt into
	// concurrency.
	concurrency := 1
	if l.concurrency > concurrency {
		concurrency = l.concurrency
	}
	g.SetLimit(concurrency)

	for i := range l.visitors {
		i := i
		g.Go(func() error {
			return l.visitors[i].Visit(fn)
		})
	}

	return g.Wait()
}