How to use the aws-xray-sdk-core.middleware function in aws-xray-sdk-core

const Database = require('@subfuzion/database').Database;
const express= require('express');
const http = require('http');
const morgan = require('morgan');

const xray = require('aws-xray-sdk-core');
const xrayExpress = require('aws-xray-sdk-express');
xray.middleware.disableCentralizedSampling();

const port = process.env.PORT || 3000;
const app = express();
const server = http.createServer(app);

let databaseConfig = Database.createStdConfig();
let db;

// install route logging middleware
app.use(morgan('dev'));

// install json body parsing middleware
app.use(express.json());

// install x-ray tracing
app.use(xrayExpress.openSegment('database-proxy.app'));

process.env.AWS_XRAY_DEBUG_MODE=1;

const axios = require('axios');
const express= require('express');
const http = require('http');
const morgan = require('morgan');

const port = process.env.PORT || 3000;
const app = express();
const server = http.createServer(app);

const xray = require('aws-xray-sdk-core');
const xrayExpress = require('aws-xray-sdk-express');
xray.middleware.disableCentralizedSampling();

const captureAxios = require('./xray-axios');

let ax = axios.create({
    baseURL: process.env.DATABASE_PROXY_URI || 'http://database-proxy:3000/'
});

captureAxios(ax);

// install route logging middleware
app.use(morgan('dev'));

// install json body parsing middleware
app.use(express.json());

// install x-ray tracing

const isProduction = (process.env.NODE_ENV === 'production');  //  True on production server.
const functionName = process.env.AWS_LAMBDA_FUNCTION_NAME || 'unknown_function';
const logName = process.env.LOGNAME || 'sigfox-aws';

const stringify = require('json-stringify-safe');

//  //////////////////////////////////////////////////////////////////////////////////// endregion
//  region Utility Functions

//  //////////////////////////////////////////////////////////////////////////////////// endregion
//  region Instrumentation Functions: Trace the execution of this Sigfox Callback across multiple Cloud Functions via AWS X-Ray

//  Allow AWS X-Ray to capture trace.
//  eslint-disable-next-line import/no-unresolved
const AWSXRay = require('aws-xray-sdk-core');
AWSXRay.middleware.setSamplingRules({
  rules: [{ description: 'sigfox-aws', service_name: '*', http_method: '*', url_path: '/*', fixed_target: 0, rate: 0.5 }],
  default: { fixed_target: 1, rate: 0.5 },
  version: 1,
});

//  Create the AWS SDK instance.
const AWS = isProduction
  ? AWSXRay.captureAWS(require('aws-sdk'))
  : require('aws-sdk');
if (isProduction) AWS.config.update({ region: process.env.AWS_REGION });
else AWS.config.loadFromPath('./aws-credentials.json');

//  TODO: Create spans and traces for logging performance.
const rootSpanStub = {
  startSpan: (/* rootSpanName, labels */) => ({
    end: () => ({}),

process.env.AWS_XRAY_DEBUG_MODE=1;

const axios = require('axios');
const express= require('express');
const http = require('http');
const morgan = require('morgan');

const port = process.env.PORT || 3000;
const app = express();
const server = http.createServer(app);

const xray = require('aws-xray-sdk-core');
const xrayExpress = require('aws-xray-sdk-express');
xray.middleware.disableCentralizedSampling();

const captureAxios = require('./xray-axios');

let ax = axios.create({
    baseURL: process.env.DATABASE_PROXY_URI || 'http://database-proxy:3000/'
});

captureAxios(ax);

// route logging middleware
app.use(morgan('dev'));

// json body parsing middleware
app.use(express.json());

// install x-ray tracing

process.env.AWS_XRAY_DEBUG_MODE=1;

const axios = require('axios');
const express= require('express');
const http = require('http');
const morgan = require('morgan');

const xray = require('aws-xray-sdk-core');
const xrayExpress = require('aws-xray-sdk-express');
xray.middleware.disableCentralizedSampling();

const captureAxios = require('./xray-axios');

const port = process.env.PORT || 3000;
const app = express();
const server = http.createServer(app);

let votesURI = process.env.VOTES_URI || 'http://votes:3000/';
let votesAPI = axios.create({
    baseURL: votesURI
});

let reportsURI = process.env.REPORTS_URI || 'http://reports:3000/';
let reportsAPI = axios.create({
    baseURL: reportsURI
});

/**
 * Express middleware module.
 *
 * Exposes Express middleware functions to enable automated data capturing on a web service. To enable on a Node.js/Express application,
 * use 'app.use(AWSXRayExpress.openSegment())' before defining your routes.  After your routes, before any extra error
 * handling middleware, use 'app.use(AWSXRayExpress.closeSegment())'.
 * Use AWSXRay.getSegment() to access the current sub/segment.
 * Otherwise, for manual mode, this appends the Segment object to the request object as req.segment.
 * @module express_mw
 */

var AWSXRay = require('aws-xray-sdk-core');

var mwUtils = AWSXRay.middleware;
var IncomingRequestData = mwUtils.IncomingRequestData;
var Segment = AWSXRay.Segment;

var expressMW = {

  /**
   * Use 'app.use(AWSXRayExpress.openSegment('defaultName'))' before defining your routes.
   * Use AWSXRay.getSegment() to access the current sub/segment.
   * Otherwise, for manual mode, this appends the Segment object to the request object as req.segment.
   * @param {string} defaultName - The default name for the segment.
   * @alias module:express_mw.openSegment
   * @returns {function}
   */

  openSegment: function openSegment(defaultName) {
    if (!defaultName || typeof defaultName !== 'string')