for len(b) > 0 {
		t, n := binary.Uvarint(b)
		if n < 0 {
			break
		}
		b = b[n:]

		typ := ChecksumType(t)
		length := typ.RawByteLen()
		if length == 0 || len(b) < length {
			break
		}
		cs := base64.StdEncoding.EncodeToString(b[:length])
		b = b[length:]
		if typ.Is(ChecksumMultipart) {
			t, n := binary.Uvarint(b)
			if n < 0 {
				break
			}