func Errorf(format string, a ...interface{}) error {
	e := fmt.Errorf(format, a...)
	ee := Error{}
	ee.msg = e.Error()
	ee.cause = errors.Unwrap(e)
	return ee
}

// Unwrap the internal error.
func (e Error) Unwrap() error { return e.cause }

// Error 'error' compatible method.
func (e Error) Error() string {
	if e.msg == "" {
		return "crypto: cause <nil>"
	}
	return e.msg
}

var (

type StorageErr string

func (h StorageErr) Error() string {
	return string(h)
}

// Collection of basic errors.
var baseErrs = []error{
	errDiskNotFound,
	errFaultyDisk,
	errFaultyRemoteDisk,
}

var baseIgnoredErrs = baseErrs

// Is a one place function which converts all os.PathError
// into a more FS object layer friendly form, converts

// specified by the developer. The purpose is to simulate errors
// that are hard to simulate in practice like DiskNotFound.
// Programmed errors are stored in errors field.
type naughtyDisk struct {
	// The real disk
	disk StorageAPI
	// Programmed errors: API call number => error to return
	errors map[int]error
	// The error to return when no error value is programmed
	defaultErr error

		}
		if quorum < readQuorum {
			toAdd.Exists = false
			toAdd.Error = errErasureReadQuorum.Error()
			toAdd.Data = nil
		}
		dataArray = append(dataArray, toAdd)
	}

	ignoredErrs := []error{
		errFileNotFound,
		errVolumeNotFound,
		errFileVersionNotFound,
		io.ErrUnexpectedEOF, // some times we would read without locks, ignore these errors

	// of splitting error text and always pretty printing the
	// red banner along with the error message. Since the error
	// message itself contains some colored text, we needed
	// to use some ANSI control escapes to cursor color state
	// and freely move in the screen.
	for _, line := range strings.Split(errMsg, "\n") {
		if len(line) == 0 {
			// No more text to print, just quit.
			break
		}

type disconnectReader struct {
	r  io.Reader
	mu sync.Mutex
}

func (d *disconnectReader) Read(p []byte) (n int, err error) {
	d.mu.Lock()
	defer d.mu.Unlock()
	if d.r != nil {
		return d.r.Read(p)
	}
	return 0, errors.New("reader closed")
}

func (d *disconnectReader) Close() error {
	d.mu.Lock()
	d.r = nil
	d.mu.Unlock()
	return nil
}

}

// Diff - returns error on first difference found in two configs.
func (s1 *ServerSystemConfig) Diff(s2 *ServerSystemConfig) error {
	ns1 := s1.NEndpoints
	ns2 := s2.NEndpoints
	if ns1 != ns2 {
		return fmt.Errorf("Expected number of endpoints %d, seen %d", ns1, ns2)
	}

	for i, cmdLine := range s1.CmdLines {
		if cmdLine != s2.CmdLines[i] {
			return fmt.Errorf("Expected command line argument %s, seen %s", cmdLine,

}

var (
	errInvalidRuleID                  = Errorf("ID length is limited to 255 characters")
	errEmptyRuleStatus                = Errorf("Status should not be empty")
	errInvalidRuleStatus              = Errorf("Status must be set to either Enabled or Disabled")
	errInvalidRuleDelMarkerExpiration = Errorf("Rule with DelMarkerExpiration cannot have tags based filtering")
)

// It does not check integrity of the stored data.
func (x xlMetaInlineData) validate() error {
	if len(x) == 0 {
		return nil
	}

	if !x.versionOK() {
		return fmt.Errorf("xlMetaInlineData: unknown version 0x%x", x[0])
	}

	sz, buf, err := msgp.ReadMapHeaderBytes(x.afterVersion())
	if err != nil {
		return fmt.Errorf("xlMetaInlineData: %w", err)
	}

	for i := uint32(0); i < sz; i++ {
		var key []byte

	}
	for i, urs := range unparsableRangeSpecs {
		rs, err := parseRequestRangeSpec(urs)
		if err == nil {
			t.Errorf("Case %d: Did not get an expected error - got %v", i, rs)
		}
		if isErrInvalidRange(err) {
			t.Errorf("Case %d: Got invalid range error instead of a parse error", i)
		}
		if rs != nil {
			t.Errorf("Case %d: Got non-nil rs though err != nil: %v", i, rs)
		}
	}

	invalidRangeSpecs := []string{
		"bytes=5-3",