w, err := zw.CreateRaw(&zip.FileHeader{
			Name:               name,
			Method:             zip.Store,
			CompressedSize64:   uint64(len(data)),
			UncompressedSize64: uint64(len(data)),
			CRC32:              crc32.ChecksumIEEE(data),
		})
		if err != nil {
			log.Fatal(err)
		}
		if _, err := w.Write(data); err != nil {
			log.Fatal(err)
		}
		seen[name] = true
		return nil
	})
	if err != nil {

		fh.UncompressedSize64 = 0

		ow = dirWriter{}
	} else {
		fh.Flags |= 0x8 // we will write a data descriptor

		fw = &fileWriter{
			zipw:      w.cw,
			compCount: &countWriter{w: w.cw},
			crc32:     crc32.NewIEEE(),
		}
		comp := w.compressor(fh.Method)
		if comp == nil {
			return nil, ErrAlgorithm
		}
		var err error
		fw.comp, err = comp(fw.compCount)
		if err != nil {
			return nil, err

		// Corrupt one of the CRC32s in the data descriptor:
		b[0x2d]++
	})
}

func returnCorruptNotStreamedZip() (r io.ReaderAt, size int64) {
	return messWith("crc32-not-streamed.zip", func(b []byte) {
		// Corrupt foo.txt's final crc32 byte, in both
		// the file header and TOC. (0x7e -> 0x7f)
		b[0x11]++
		b[0x9d]++

		// TODO(bradfitz): add a new test that only corrupts

				}
			}
			f, err := w.CreateHeader(&FileHeader{
				Name:   filename,
				Method: Store,
			})
			if err != nil {
				t.Fatal(err)
			}
			f.(*fileWriter).crc32 = fakeHash32{}
			size := wantOff - fileHeaderLen - uint64(len(filename)) - dataDescriptorLen
			if _, err := io.CopyN(f, zeros{}, int64(size)); err != nil {
				t.Fatal(err)
			}
			if err := w.Close(); err != nil {