co-body v5.0.3 reproduce

index.js

'use strict';

var koa = require('koa');
var bodyParse = require('koa-bodyparser');
var app = new koa();

app.use(function *(next) {
    let bodyData = [];

    this.req.on('data', (chunk) => {
        bodyData.push(chunk);
    });

    this.req.on('end',  () => {
        this.req.rawBody = Buffer.concat(bodyData).toString();
    });

    return yield next;
});

app.use(bodyParse());

app.listen(2000, function() {
    let data = JSON.stringify({foo:'bar'});
    var request = require('http').request({
        hostname: '127.0.0.1',
        port: 2000,
        method: 'POST',
        path: '/foo',
        headers: {
            'Content-Type' : 'application/json',
        }
    }, function (resp) {
        resp.pipe(process.stdout);
    });
    request.end(data);
});