Incorrect Data (empty body) returned through req: lambda + API gateway

### app.post("/path/path", (req, res) => { }

I am not sure what exactly is the issue is, but it seems that my **req** variable contains weird data from aws- api gateway. When I try log the contents I get a circular error. The data exists in the event variable with the following code in my index .js:

```
const awsServerlessExpress = require('aws-serverless-express');
const app = require('./app');

const server = awsServerlessExpress.createServer(app);

exports.handler = (event, context) => {
console.log(`EVENT: ${JSON.stringify(event)}`);
return awsServerlessExpress.proxy(server, event, context, 'PROMISE').promise;
};

```

Then in my app.js i have the following code:

``` // app modules
var express = require("express");
var bodyParser = require("body-parser");
var awsServerlessExpressMiddleware = require("aws-serverless-express/middleware");

// declare a new express app
var app = express();
app.use(bodyParser.json());
app.use(awsServerlessExpressMiddleware.eventContext());

// Enable CORS for all methods
app.use(function (req, res, next) {
res.header("Access-Control-Allow-Origin", "*");
res.header("Access-Control-Allow-Headers", "*");
next();
});

app.post("/NotifyUrl-crprod/payfast", (req, res) => {

console.log("body" + Object.keys(req), Object.values(req));
console.log("body1" + req);
})
```
The req parameter contains stuff except the data that was actually sent through from api gateway, i.e. the data (body) doesn't exist in the **req**, even though it exists in **event** . The screenshots below are printouts of the keys and values that are printed out and the event variable data . These keys are not the issue, the issue is that the desired data doesn't appear at all **req.body** is empty. logging out the **req** will through a circular reference error which is okay, but the desired data is not present.

These are the different dependency version being used:
```
"aws-serverless-express": "^3.4.0",
"body-parser": "^1.17.1",
"express": "^4.15.2",
```

The below event printout screenshot is only a fraction of the full data that is contained in req.


index.js と app.js から始め、次に、ログに記録された API Gateway イベントと、/NotifyUrl-crprod/payfast の Express ハンドラーに公開されるデータを比較します。POST リクエストを再現し、req.body に送信された payload が含まれているか確認します。ハンドラーでリクエストボディを利用できるか、またはそれが欠落する原因となっている統合境界を特定できれば完了です。

索引モデルが issue の本文から書いたものです。