StatusConflict                     = 409 // RFC 9110, 15.5.10
	StatusGone                         = 410 // RFC 9110, 15.5.11
	StatusLengthRequired               = 411 // RFC 9110, 15.5.12
	StatusPreconditionFailed           = 412 // RFC 9110, 15.5.13
	StatusRequestEntityTooLarge        = 413 // RFC 9110, 15.5.14
	StatusRequestURITooLong            = 414 // RFC 9110, 15.5.15

		// down, this is for orchestrators to know if we can safely
		// take this server down, return appropriate error.
		if opts.Maintenance {
			writeResponse(w, http.StatusPreconditionFailed, nil, mimeNone)
		} else {
			writeResponse(w, http.StatusServiceUnavailable, nil, mimeNone)
		}
		return
	}
	writeResponse(w, http.StatusOK, nil, mimeNone)
}

	"Conflict":                        http.StatusConflict,
	"Gone":                            http.StatusGone,
	"Length Required":                 http.StatusLengthRequired,
	"Precondition Failed":             http.StatusPreconditionFailed,
	"Request Entity Too Large":        http.StatusRequestEntityTooLarge,
	"Request URI Too Long":            http.StatusRequestURITooLong,
	"Unsupported Media Type":          http.StatusUnsupportedMediaType,

// resulted in sending StatusNotModified or StatusPreconditionFailed.
func checkPreconditions(w ResponseWriter, r *Request, modtime time.Time) (done bool, rangeHeader string) {
	// This function carefully follows RFC 7232 section 6.
	ch := checkIfMatch(w, r)
	if ch == condNone {
		ch = checkIfUnmodifiedSince(r, modtime)
	}
	if ch == condFalse {
		w.WriteHeader(StatusPreconditionFailed)
		return true, ""
	}

		// with the caller to take the client offline purpose
		// fully it should make sure to respond with '412'
		// instead, see cmd/storage-rest-server.go for ideas.
		if c.HealthCheckFn != nil && resp.StatusCode == http.StatusPreconditionFailed {
			err = fmt.Errorf("Marking %s offline temporarily; caused by PreconditionFailed with drive ID mismatch", c.url.Host)
			logger.LogOnceIf(ctx, logSubsys, err, c.url.Host)
			c.MarkOffline(err)
		}

				writeErrorResponseHeadersOnly(w, errorCodes.ToAPIErr(s3Error))
				return
			}

			okSt := (ci.StatusCode == http.StatusOK || ci.StatusCode == http.StatusPartialContent ||
				ci.StatusCode == http.StatusPreconditionFailed || ci.StatusCode == http.StatusNotModified)
			if okSt {
				ci.WriteHeaders(w, func() {
					// set common headers
					setCommonHeaders(w)
				}, func() {

	// http.StatusUnsupportedMediaType, http.StatusNotAcceptable,
	// http.StatusBadRequest, http.StatusUnauthorized, http.StatusForbidden,
	// http.StatusRequestTimeout, http.StatusConflict, http.StatusPreconditionFailed,
	// http.StatusUnprocessableEntity, http.StatusInternalServerError,
	// http.StatusServiceUnavailable
	// and api error codes
	// Note that if we specify a versioned Status object here, we may need to

	return getStorageViaEndpoint(s.endpoint)
}

func (s *storageRESTServer) writeErrorResponse(w http.ResponseWriter, err error) {
	err = unwrapAll(err)
	switch err {
	case errDiskStale:
		w.WriteHeader(http.StatusPreconditionFailed)
	case errFileNotFound, errFileVersionNotFound:
		w.WriteHeader(http.StatusNotFound)
	case errInvalidAccessKeyID, errAccessKeyDisabled, errNoAuthToken, errMalformedAuth, errAuthentication, errSkewedAuthTime:

	// Again, obtain the object info.
	// This time setting "If-Unmodified-Since" to a time after the object is modified.
	// As documented above, expecting http.StatusPreconditionFailed.
	request, err = newTestSignedRequest(http.MethodHead, getHeadObjectURL(s.endPoint, bucketName, objectName),
		0, nil, s.accessKey, s.secretKey, s.signer)
	c.Assert(err, nil)

	},
	ErrPreconditionFailed: {
		Code:           "PreconditionFailed",
		Description:    "At least one of the pre-conditions you specified did not hold",
		HTTPStatusCode: http.StatusPreconditionFailed,
	},
	ErrRequestTimeTooSkewed: {
		Code:           "RequestTimeTooSkewed",
		Description:    "The difference between the request time and the server's time is too large.",
		HTTPStatusCode: http.StatusForbidden,