if c == nil {
		return nil
	}
	var tmp [binary.MaxVarintLen32]byte
	n := binary.PutUvarint(tmp[:], uint64(c.Type))
	crc := c.Raw
	if len(crc) != c.Type.RawByteLen() {
		return b
	}
	b = append(b, tmp[:n]...)
	b = append(b, crc...)
	if c.Type.Is(ChecksumMultipart) {
		var checksums int
		// Ensure we don't divide by 0:

	0, 0, 0, 41, // headers byte-length.
	139, 161, 157, 242, // prelude crc.
	13, ':', 'm', 'e', 's', 's', 'a', 'g', 'e', '-', 't', 'y', 'p', 'e', 7, 0, 5, 'e', 'v', 'e', 'n', 't', // headers.
	11, ':', 'e', 'v', 'e', 'n', 't', '-', 't', 'y', 'p', 'e', 7, 0, 4, 'C', 'o', 'n', 't', // headers.
	156, 134, 74, 13, // message crc.
}

// Refer genProgressHeader().
var progressHeader = []byte{

					return nil, err
				}
			case 1, 2:
				v, b, err := msgp.ReadBytesZC(b)
				if err != nil {
					return nil, err
				}
				if _, nbuf, err := msgp.ReadUint32Bytes(b); err == nil {
					// Read metadata CRC (added in v2, ignore if not found)
					b = nbuf
				}

				_, err = msgp.CopyToJSON(buf, bytes.NewReader(v))
				if err != nil {
					return nil, err
				}
				data = b
			case 3:

}

// ContentCRCType returns the content checksum type.
func (r *Reader) ContentCRCType() ChecksumType {
	return r.contentHash.Type
}

// ContentCRC returns the content crc if set.
func (r *Reader) ContentCRC() map[string]string {
	if r.contentHash.Type == ChecksumNone || !r.contentHash.Valid() {
		return nil
	}
	if r.contentHash.Type.Trailing() {

				hash.ChecksumSHA256.String(): part.ChecksumSHA256,
			}
			if wantCS[checksumType.String()] != crc {
				return oi, InvalidPart{
					PartNumber: part.PartNumber,
					ExpETag:    wantCS[checksumType.String()],
					GotETag:    crc,
				}
			}
			cs := hash.NewChecksumString(checksumType.String(), crc)
			if !cs.Valid() {
				return oi, InvalidPart{
					PartNumber: part.PartNumber,
				}
			}

				err = msgp.WrapError(err, "ModTime")
				return
			}
		case "index":
			z.Index, err = dc.ReadBytes(z.Index)
			if err != nil {
				err = msgp.WrapError(err, "Index")
				return
			}
		case "crc":
			var zb0002 uint32
			zb0002, err = dc.ReadMapHeader()
			if err != nil {
				err = msgp.WrapError(err, "Checksums")
				return
			}
			if z.Checksums == nil {