func (sto *s3Storage) slurpAll() {
	var mu sync.Mutex
	var nblobs, nbytes int64

	errc := make(chan error)
	for i := 0; i < 16; i++ {
		pfx := fmt.Sprintf("sha1-%x", i)
		log.Printf("Doing prefix %q", pfx)
		ctx := context.New()
		go func() {
			err := blobserver.EnumerateAllFrom(ctx, sto, pfx, func(sb blob.SizedRef) error {
				if !strings.HasPrefix(sb.Ref.String(), pfx) {
					log.Printf("Ref %q doesn't have prefix %q", sb.Ref.String(), pfx)
					ctx.Cancel()
					return context.ErrCanceled
				}
				mu.Lock()
				nblobs++
				nbytes += int64(sb.Size)
				mu.Unlock()
				return nil
			})
			log.Printf("Enum prefix %q", pfx)
			errc <- err
		}()
	}
	var lastErr error
	for i := 0; i < 16; i++ {
		if err := <-errc; err != nil {
			log.Printf("enumerate error: %v", err)
			lastErr = err
		}
	}
	log.Printf("Done enumerating all: %d blobs, %d bytes; err=%v", nblobs, nbytes, lastErr)
}