How to use the aws-xray-sdk-express.closeSegment function in aws-xray-sdk-express

console.log('GET /results');
    console.log(`web -> GET ${reportsURI}/results`);
    let result = await reportsAPI.get('/results');
    console.log('resp: %j', result.data);
    // result.data contains an object
    // { success: , result: { voter_id: , vote: } }
    // Just passing response through
    // Expect an object with vote count: { success: true, result: { a: X, b: X } }
    res.send(result.data);
  } catch (err) {
    console.log('ERROR: GET /results: %s', err.message || err.response || err);
    res.status(500).send({ success: false, reason: 'internal error' });
  }
});

app.use(xrayExpress.closeSegment());

// initialize and start running
(async () => {
  try {
    await new Promise(resolve => {
      server.listen(port, () => {
        console.log(`listening on port ${port}`);
        resolve();
      });
    });

  } catch (err) {
    console.log(err);
    process.exit(1);
  }
})();

});

// results route handler
app.get('/results', async (req, res) => {
  try {
    console.log('GET /results');
    let result = await db.tallyVotes();
    console.log('results: %j', result);
    res.send({ success: true, result: result });
  } catch (err) {
    console.log('ERROR GET /results: %j', err);
    res.send(500, { success: false, reason: err.message });
  }
});

app.use(xrayExpress.closeSegment());

// initialize and start running
(async () => {
  try {
    // initialize database client for querying vote results
    db = new Database(databaseConfig);
    console.log(`connecting to database at (${db.connectionURL})`);
    await db.connect();
    console.log(`connected to database (${db.connectionURL})`);
    server.listen(port, () => console.log(`listening on port ${port}`));
  } catch (err) {
    console.log(err);
    process.exit(1);
  }
})();

let r = data.result; 
      console.log(`data: ${r}`)
      r.totalVotes = r.a + r.b;
      r.version = "2.0"
    // ex: { success: true, result: { a: X, b: X, totalVotes: X } }
      console.log(`v2 data: ${r}`)
    }

    res.send(data);
  } catch (err) {
    console.log('ERROR: GET /results: %s', err.message || err.response || err);
    res.status(500).send({ success: false, reason: 'internal error' });
  }
});

app.use(xrayExpress.closeSegment());

// initialize and start running
(async () => {
  try {
    await new Promise(resolve => {
      server.listen(port, () => {
        console.log(`listening on port ${port}`);
        resolve();
      });
    });
  
  } catch (err) {
    console.log(err);
    process.exit(1);
  }
})();

try {
    console.log('POST /vote: %j', req.body);
    let v = req.body;
    let result = await ax.post('/vote', v);
    let data = result.data;
    // result.data contains an object
    // { success: , result: { voter_id: , vote: } }
    console.log('data: ', data);
    res.send(data);
  } catch (err) {
    console.log('ERROR: POST /vote:', err);
    res.status(500).send({ success: false, reason: err.message })
  }
});

app.use(xrayExpress.closeSegment());

// initialize and start running
(async () => {
  try {
    await new Promise(resolve => {
      server.listen(port, () => {
        console.log(`listening on port ${port}`);
        resolve();
      });
    });
  
  } catch (err) {
    console.log(err);
    process.exit(1);
  }
})();