// JoinLoaders - joins multiple loaders into a single loader. The returned
// loader will call each of the given loaders in order. If any of the loaders
// return an error, the returned loader will return that error.
func JoinLoaders(loaders ...MetricsLoaderFn) MetricsLoaderFn {
	return func(ctx context.Context, m MetricValues, c *metricsCache) error {
		for _, loader := range loaders {
			if err := loader(ctx, m, c); err != nil {

	}
}

var ssecUnsealObjectKeyTests = []struct {
	Headers        http.Header
	Bucket, Object string
	Metadata       map[string]string

	ExpectedErr error
}{
	{ // 0 - Valid HTTP headers and valid metadata entries for bucket/object
		Headers: http.Header{
			"X-Amz-Server-Side-Encryption-Customer-Algorithm": []string{"AES256"},

				"response-content-type": "application/json",
			},
			headers: map[string]string{
				"X-Amz-Date":           now.Format(iso8601Format),
				"X-Amz-Content-Sha256": payloadSHA256,
			},
			region:   "",
			expected: ErrSignatureDoesNotMatch,
		},
		// (9) Should error with unsigned headers.
		{
			queryParams: map[string]string{
				"X-Amz-Algorithm":       signV4Algorithm,

	}

	// Since the list of signed headers value contained `expect`, the default value of `100-continue` will be added to extracted signed headers.
	if extractedExpect != expectedExpect {
		t.Errorf("expect header incorrect value: expected `%s`, got `%s`", expectedExpect, extractedExpect)
	}

	// case where the headers don't contain the one of the signed header in the signed headers list.

		// If request header key is not in ignored headers, then add it.
		if _, ok := ignoredStreamingHeaders[http.CanonicalHeaderKey(k)]; !ok {
			headerMap[strings.ToLower(k)] = vv
		}
	}

	// Get header keys.
	headers := []string{"host"}
	for k := range headerMap {
		headers = append(headers, k)
	}
	sort.Strings(headers)

	// Get canonical headers.
	var buf bytes.Buffer
	for _, k := range headers {

					Method:   r.Method,
					RawQuery: redactLDAPPwd(r.URL.RawQuery),
					Client:   handlers.GetSourceIP(r),
					Headers:  reqHeaders,
					Path:     reqPath,
					Body:     reqRecorder.Data(),
				},
				RespInfo: madmin.TraceResponseInfo{
					Time:       reqEndTime,
					Headers:    respRecorder.Header().Clone(),
					StatusCode: respRecorder.StatusCode,
					Body:       respRecorder.Body(),
				},

		if testCase.expectedCode != actualCode {
			t.Errorf("Test %d: Expected the APIErrCode to be %d, but instead found %d", i+1, testCase.expectedCode, actualCode)
		}
	}
}

// Tests validate metadata extraction from http headers.
func TestExtractMetadataHeaders(t *testing.T) {
	testCases := []struct {
		header     http.Header
		metadata   map[string]string
		shouldFail bool
	}{
		// Validate if there a known 'content-type'.
		{

	buf.WriteString("Records")

	fmt.Println(buf.Bytes())
}

// Continuation Message
// ====================
// Header specification
// --------------------
// Continuation messages contain two headers, as follows:
// https://docs.aws.amazon.com/AmazonS3/latest/API/images/s3select-frame-diagram-cont.png
//
// Payload specification
// ---------------------
// Continuation messages have no payload.

	v := MRFReplicateEntries{
		Entries: entries,
		Version: mrfMetaVersion,
	}

	p.persistToDrive(ctx, v)
}

// load mrf entries from disk
func (p *ReplicationPool) loadMRF() (mrfRec MRFReplicateEntries, err error) {
	loadMRF := func(rc io.ReadCloser) (re MRFReplicateEntries, err error) {
		defer rc.Close()

		if !p.initialized() {
			return re, nil
		}
		var data [4]byte

// https://docs.aws.amazon.com/AmazonS3/latest/userguide/checking-object-integrity.html
// Returns ErrInvalidChecksum if a problem with the checksum is found.
func (r *Reader) AddChecksumNoTrailer(headers http.Header, ignoreValue bool) error {
	cs, err := GetContentChecksum(headers)
	if err != nil {
		return ErrInvalidChecksum
	}
	if cs == nil {
		return nil
	}
	r.contentHash = *cs
	return r.AddNonTrailingChecksum(cs, ignoreValue)
}