// Generate string error response.
	writeResponse(w, err.HTTPStatusCode, []byte(err.Description), mimeNone)
}

// writeErrorResponseJSON - writes error response in JSON format;
// useful for admin APIs.
func writeErrorResponseJSON(ctx context.Context, w http.ResponseWriter, err APIError, reqURL *url.URL) {
	// Generate error response.

		default:
			desc = fmt.Sprintf("Unexpected client 'admin' API version found '%s', expected '%s', please downgrade the client to older releases", version, madmin.AdminAPIVersion)
		}
		writeErrorResponseJSON(r.Context(), w, APIError{
			Code:           "XMinioAdminVersionMismatch",
			Description:    desc,
			HTTPStatusCode: http.StatusUpgradeRequired,
		}, r.URL)
	default:

		// Check if object layer is available, if not return error early.
		if !handlerFlags.Has(noObjLayerFlag) {
			objectAPI := newObjectLayerFn()
			if objectAPI == nil || globalNotificationSys == nil {
				writeErrorResponseJSON(r.Context(), w, errorCodes.ToAPIErr(ErrServerNotInitialized), r.URL)
				return
			}
		}

		// Apply http tracing "middleware" based on presence of flag.
		var f2 http.HandlerFunc

		if ok {
			tc.FuncName = funcName
			tc.ResponseRecorder.LogErrBody = true
		}

		mfs, err := gatherers.Gather()
		if err != nil && len(mfs) == 0 {
			writeErrorResponseJSON(r.Context(), w, toAdminAPIErr(r.Context(), err), r.URL)
			return
		}

		contentType := expfmt.Negotiate(r.Header)
		w.Header().Set("Content-Type", string(contentType))