}

var errorWriterToTests = []errorWriterToTest{
	{1, 0, nil, io.ErrClosedPipe, io.ErrClosedPipe},
	{0, 1, io.ErrClosedPipe, nil, io.ErrClosedPipe},
	{0, 0, io.ErrUnexpectedEOF, io.ErrClosedPipe, io.ErrUnexpectedEOF},
	{0, 1, io.EOF, nil, nil},
}

func TestReaderWriteToErrors(t *testing.T) {
	for i, rw := range errorWriterToTests {
		r := NewReader(rw)

	}
	readMore := func(n int64) error {
		has := int64(len(buf))
		if has >= n {
			return nil
		}
		if hasFull || n > size {
			return io.ErrUnexpectedEOF
		}
		extra := n - has
		if int64(cap(buf)) >= n {
			// Extend since we have enough space.
			buf = buf[:n]
		} else {
			buf = append(buf, make([]byte, extra)...)
		}

	return nil
}

// deserialize the supplied byte slice into the cache.
func (d *dataUsageCache) deserialize(r io.Reader) error {
	var b [1]byte
	n, _ := r.Read(b[:])
	if n != 1 {
		return io.ErrUnexpectedEOF
	}
	ver := int(b[0])
	switch ver {
	case dataUsageCacheVerV1:
		return errors.New("cache version deprecated (will autoupdate)")
	case dataUsageCacheVerV2:
		// Zstd compressed.

		errors.Is(err, errConfigNotFound) ||
		errors.Is(err, context.DeadlineExceeded) ||
		errors.Is(err, errErasureWriteQuorum) ||
		errors.Is(err, errErasureReadQuorum) ||
		errors.Is(err, io.ErrUnexpectedEOF) ||
		errors.As(err, &rquorum) ||
		errors.As(err, &wquorum) ||
		isErrObjectNotFound(err) ||
		isErrBucketNotFound(err) ||
		errors.Is(err, os.ErrDeadlineExceeded) ||
		notInitialized
}

			length := binary.LittleEndian.Uint32(tmp[:])
			n, err := io.CopyBuffer(w, io.LimitReader(respBody, int64(length)), buf)
			if err != nil {
				return err
			}
			if n != int64(length) {
				return io.ErrUnexpectedEOF
			}
			continue
		case 32:
			continue
		default:
			return fmt.Errorf("unexpected filler byte: %d", tmp[0])
		}
	}
}

	defer cancel()
	totalRx := int64(0)
	connectTime := time.Now()
	for {
		n, err := io.CopyN(xioutil.Discard, r.Body, 128*humanize.KiByte)
		if err != nil && err != io.EOF && err != io.ErrUnexpectedEOF {
			// would mean the network is not stable. Logging here will help in debugging network issues.
			if time.Since(connectTime) < (globalNetPerfMinDuration - time.Second) {
				adminLogIf(ctx, err)
			}
		}

// read. On return, n == len(buf) if and only if err == nil. n == 0
// for io.EOF.
//
// If an EOF happens after reading some but not all the bytes,
// ReadFile returns ErrUnexpectedEOF.
//
// If the BitrotVerifier is not nil or not verified ReadFile
// tries to verify whether the disk has bitrot.
//
// Additionally ReadFile also starts reading from an offset. ReadFile

pkg io, type WriterTo interface, WriteTo(Writer) (int64, error)
pkg io, var EOF error
pkg io, var ErrClosedPipe error
pkg io, var ErrShortBuffer error
pkg io, var ErrShortWrite error
pkg io, var ErrUnexpectedEOF error
pkg io/ioutil, func NopCloser(io.Reader) io.ReadCloser
pkg io/ioutil, func ReadAll(io.Reader) ([]uint8, error)
pkg io/ioutil, func ReadDir(string) ([]os.FileInfo, error)