}
	if m.Flags&FlagCRCxxh3 != 0 {
		const hashLen = 4
		if len(h) < hashLen {
			return nil, nil, fmt.Errorf("want crc len 4, got %v", len(h))
		}
		got := uint32(xxh3.Hash(b[:len(b)-hashLen]))
		want := binary.LittleEndian.Uint32(h[len(h)-hashLen:])
		if got != want {
			return nil, nil, fmt.Errorf("crc mismatch: 0x%08x (given) != 0x%08x (bytes)", want, got)
		}
		h = h[:len(h)-hashLen]
	}
	// Extract subroute if any.