Node.js Nodejs https函数需要等待url json响应，并将其作为在客户端打印的响应传递回调用的express模块

我正在尝试使用nodejs express模块托管一个服务器，当它收到来自客户端的点击时，https模块将尝试点击另一个url并获取json响应保存它，并将此响应作为对其点击的响应提供回客户端。PFB my code可以在服务器端而不是客户端打印响应，PFB my code可以在服务器端而不是客户端打印响应。我尝试了下面的注释方式，但得到了空答案。我打算用卷发去快车

const express = require('express')
const app = express()
const port = 3000
var url = require('url');
var https = require('https');
var HttpsProxyAgent = require('https-proxy-agent')
var responsedata =  "";

function delay() {
  return new Promise(function(resolve, reject) {
    setTimeout(function() {
      resolve(42);
    }, 10000);
  });
}

app.get('/', async (request, response) => {
                // HTTP/HTTPS proxy to connect to
                        var proxy = process.env.http_proxy || 'http://bc-proxy-vip.de.pri.o2.com:8080';
                        console.log('using proxy server %j', proxy);
                // HTTPS endpoint for the proxy to connect to
                        var endpoint = process.argv[2] || 'https://api.spatialbuzz.com/api/coverage/2010-11-22/near/address/ehrwalder%20str%2064%2081377/customer/CSIEK3QbW2cycVMMWXddBR4xZl5yVA5QAVo/auth/84120D1A::F5305563';
                        console.log('attempting to GET %j', endpoint);
                        var options = url.parse(endpoint);
                // Creating an instance of the `HttpsProxyAgent` class with the proxy server information
                        var agent = new HttpsProxyAgent(proxy);
                        options.agent = agent;

                        var req = await  https.request(options, function(res) {
                          //console.log('STATUS: ' + res.statusCode);
                          //console.log('HEADERS: ' + JSON.stringify(res.headers));
                        res.setEncoding('utf8');
                        console.log(res.data); // *** null value undefined
                        res.pipe(process.stdout); // *** Working fine prints json resonse in server side 
                        responsedata = res.data;
                           ///responsedata1 = res.on('data', function (chunk) {
                                //console.log('BODY: ' + chunk);
                                //responsedata = ('BODY: ' + chunk);
                                //responsedata += chunk;
                                //console.log(responsedata);
                                //return (responsedata);
                                
                          });
                        //console.log(responsedata); // *** Printing null value
                        //   });
                        
                       // req.on('error', (e) => {
                       //   console.log(`problem with request: ${e.message}`);
                      //});
                        req.end();
                response.send("Helloworld") // *** WORKING printing helloworld in client side
                //response.send('responsedata'); // NOT WORKING printing null repsonse}) 

app.listen(port, () => {
  console.log(`Example app listening at http://localhost:${port}`)
})