func (tr *Reader) readHeader() (*Header, *block, error) {
	// Two blocks of zero bytes marks the end of the archive.
	if _, err := io.ReadFull(tr.r, tr.blk[:]); err != nil {
		return nil, nil, err // EOF is okay here; exactly 0 bytes read
	}
	if bytes.Equal(tr.blk[:], zeroBlock[:]) {
		if _, err := io.ReadFull(tr.r, tr.blk[:]); err != nil {
			return nil, nil, err // EOF is okay here; exactly 1 block of zeros read
		}

	x = Element{1, 1, 1, 1, 1}
	x2.Multiply(&x, &x)
	x2sq.Square(&x)

	if x2 != x2sq {
		t.Fatalf("all ones failed\nmul: %x\nsqr: %x\n", x2, x2sq)
	}

	var bytes [32]byte

	_, err := io.ReadFull(rand.Reader, bytes[:])
	if err != nil {
		t.Fatal(err)
	}
	x.SetBytes(bytes[:])

	x2.Multiply(&x, &x)
	x2sq.Square(&x)

	if x2 != x2sq {

		// The file offset maintained by the loop corresponds to &buf[tiny].
		// buf[start:tiny] is left over from previous iteration.
		// After reading n bytes into buf[tiny:], we process buf[start:tiny+n].
		n, err := io.ReadFull(r, buf[tiny:])
		if err != io.ErrUnexpectedEOF && err != io.EOF && err != nil {
			return nil, [32]byte{}, err
		}

		// Process any matches.
		for {
			i := bytes.Index(buf[start:tiny+n], idBytes)
			if i < 0 {

			asyncWriters <- struct{}{}
			b := poolBuf128k.Get().([]byte)
			if cap(b) < int(header.Size) {
				b = make([]byte, smallFileThreshold)
			}
			b = b[:header.Size]
			if _, err := io.ReadFull(tarReader, b); err != nil {
				return err
			}
			wg.Add(1)
			go func(name string, fi fs.FileInfo, b []byte) {
				rc := disconnectReader{r: bytes.NewReader(b)}
				defer func() {
					rc.Close()

	}
	res, err := http.ReadResponse(bufio.NewReader(conn), req)
	if err != nil {
		t.Fatalf("ReadResponse: %v", err)
	}
	defer res.Body.Close()
	var buf [5000]byte
	n, err := io.ReadFull(res.Body, buf[:])
	if err != nil {
		t.Fatalf("ReadFull: %d bytes, %v", n, err)
	}

	if !handlerRunning() {
		t.Fatalf("pre-conn.Close, expected handler to still be running")
	}
	conn.Close()
	closed := time.Now()

		})
		errChan <- client.Handshake()
	}()

	var header [5]byte
	if _, err := io.ReadFull(s, header[:]); err != nil {
		t.Fatal(err)
	}
	recordLen := int(header[3])<<8 | int(header[4])

	record := make([]byte, recordLen)
	if _, err := io.ReadFull(s, record); err != nil {
		t.Fatal(err)
	}

	serverHello := &serverHelloMsg{
		vers:         VersionTLS12,

	var wg sync.WaitGroup
	defer wg.Wait()

	pingPonger := func(c net.Conn) {
		defer wg.Done()
		buf := make([]byte, 8)
		var prev uint64
		for {
			if _, err := io.ReadFull(c, buf); err != nil {
				if err == io.EOF {
					break
				}
				t.Errorf("unexpected Read error: %v", err)
			}

			v := binary.LittleEndian.Uint64(buf)
			binary.LittleEndian.PutUint64(buf, v+1)

			dataCtx := tt.dataCtx
			if dataCtx == nil {
				dataCtx = value.DefaultContext([]byte(""))
			}
			for _, l := range lengths {
				data := make([]byte, l)
				if _, err := io.ReadFull(rand.Reader, data); err != nil {
					t.Fatalf("unable to read sufficient random bytes: %v", err)
				}
				original := append([]byte{}, data...)

				ciphertext, err := tt.t.TransformToStorage(ctx, data, dataCtx)

	// indicates a possible race with someone editing the file, so we prefer to
	// stop to avoid corrupting it.)
	src := make([]byte, size+1)
	n, err := io.ReadFull(in, src)
	switch err {
	case nil, io.EOF, io.ErrUnexpectedEOF:
		// io.ReadFull returns io.EOF (for an empty file) or io.ErrUnexpectedEOF
		// (for a non-empty file) if the file was changed unexpectedly. Continue
		// with comparing file sizes in those cases.

// nonZeroRandomBytes fills the given slice with non-zero random octets.
func nonZeroRandomBytes(s []byte, random io.Reader) (err error) {
	_, err = io.ReadFull(random, s)
	if err != nil {
		return
	}

	for i := 0; i < len(s); i++ {
		for s[i] == 0 {
			_, err = io.ReadFull(random, s[i:i+1])
			if err != nil {
				return
			}
			// In tests, the PRNG may return all zeros so we do
			// this to break the loop.