case xhttp.StorageClass:
		case xhttp.ObjectSize:
		case xhttp.ObjectParts:
		default:
			apiErr = errorCodes.ToAPIErr(ErrInvalidAttributeName)
			argumentName = strings.ToLower(xhttp.AmzObjectAttributes)
			argumentValue = tag
			valid = false
			return
		}
	}

	return
}

func parseObjectAttributes(h http.Header) (attributes map[string]struct{}) {
	attributes = make(map[string]struct{})

func setEventStreamHeaders(w http.ResponseWriter) {
	w.Header().Set(xhttp.ContentType, "text/event-stream")
	w.Header().Set(xhttp.CacheControl, "no-cache") // nginx to turn off buffering
	w.Header().Set("X-Accel-Buffering", "no")      // nginx to turn off buffering
}

// Write http common headers
func setCommonHeaders(w http.ResponseWriter) {
	// Set the "Server" http header.
	w.Header().Set(xhttp.ServerInfo, MinioStoreName)

			recorder := httptest.NewRecorder()
			request := httptest.NewRequest(http.MethodHead, "/bucket/a", bytes.NewReader([]byte{}))
			request.Header.Set(xhttp.IfNoneMatch, tc.ifNoneMatch)
			request.Header.Set(xhttp.IfModifiedSince, tc.ifModifiedSince)
			request.Header.Set(xhttp.IfMatch, tc.ifMatch)
			request.Header.Set(xhttp.IfUnmodifiedSince, tc.ifUnmodifiedSince)

		}
	}

	for _, objLock := range []string{
		xhttp.AmzObjectLockMode,
		xhttp.AmzObjectLockLegalHold,
		xhttp.AmzObjectLockRetainUntilDate,
	} {
		if values, ok := cloneHeader[objLock]; ok {
			args[strings.TrimPrefix(objLock, "X-Amz-")] = values
		}
		cloneHeader.Del(objLock)
	}

	for key, values := range cloneHeader {
		if strings.EqualFold(key, xhttp.AmzObjectTagging) {
			continue
		}

	if _, ok := metadata[strings.ToLower(xhttp.ContentType)]; !ok {
		metadata[strings.ToLower(xhttp.ContentType)] = "binary/octet-stream"
	}

	// https://github.com/google/security-research/security/advisories/GHSA-76wf-9vgp-pj7w
	for k := range metadata {
		if equals(k, xhttp.AmzMetaUnencryptedContentLength, xhttp.AmzMetaUnencryptedContentMD5) {
			delete(metadata, k)
		}
	}

		writeResponse(w, http.StatusServiceUnavailable, nil, mimeNone)
		return nil
	}

	if !globalBucketMetadataSys.Initialized() {
		w.Header().Set(xhttp.MinIOServerStatus, "bucket-metadata-offline")
		writeResponse(w, http.StatusServiceUnavailable, nil, mimeNone)
		return nil
	}

	if !globalIAMSys.Initialized() {
		w.Header().Set(xhttp.MinIOServerStatus, "iam-offline")

func corsHandler(handler http.Handler) http.Handler {
	commonS3Headers := []string{
		xhttp.Date,
		xhttp.ETag,
		xhttp.ServerInfo,
		xhttp.Connection,
		xhttp.AcceptRanges,
		xhttp.ContentRange,
		xhttp.ContentEncoding,
		xhttp.ContentLength,
		xhttp.ContentType,
		xhttp.ContentDisposition,
		xhttp.LastModified,
		xhttp.ContentLanguage,
		xhttp.CacheControl,
		xhttp.RetryAfter,

	delete(metadata, xhttp.AmzServerSideEncryption)
	delete(metadata, xhttp.AmzServerSideEncryptionKmsID)
	delete(metadata, xhttp.AmzServerSideEncryptionKmsContext)
	delete(metadata, xhttp.AmzServerSideEncryptionCustomerAlgorithm)
	delete(metadata, xhttp.AmzServerSideEncryptionCustomerKey)
	delete(metadata, xhttp.AmzServerSideEncryptionCustomerKeyMD5)
	delete(metadata, xhttp.AmzServerSideEncryptionCopyCustomerAlgorithm)

	case crypto.S3:
		m[xhttp.AmzServerSideEncryption] = xhttp.AmzEncryptionAES
	case crypto.S3KMS:
		m[xhttp.AmzServerSideEncryption] = xhttp.AmzEncryptionKMS
		m[xhttp.AmzServerSideEncryptionKmsID] = kmsKeyIDFromMetadata(metadata)
		if kmsCtx, ok := metadata[crypto.MetaContext]; ok {
			m[xhttp.AmzServerSideEncryptionKmsContext] = kmsCtx
		}
	case crypto.SSEC:

		w.Header().Set(xhttp.LastModified, objInfo.ModTime.UTC().Format(http.TimeFormat))

		if objInfo.ETag != "" {
			w.Header()[xhttp.ETag] = []string{"\"" + objInfo.ETag + "\""}
		}
	}

	// If-Match : Return the object only if its entity tag (ETag) is the same as the one specified;
	// otherwise return a 412 (precondition failed).
	ifMatchETagHeader := r.Header.Get(xhttp.IfMatch)
	if ifMatchETagHeader != "" {