node-mocks-http EventEmitter issue

index.js

var EventEmitter = require('events').EventEmitter;
var express = require('express');
var httpMocks = require('node-mocks-http');

var res = httpMocks.createResponse({
  eventEmitter: EventEmitter            // works, but is somewhat counterintuitive
  // eventEmitter: new EventEmitter()   // this is what I would expect to work
});
var req = httpMocks.createRequest({
  method: 'GET',
  url: '/'
});

function someAsyncIo(cb) {
  cb(null);
}

var router = express.Router();
router.get('/', function(req, res, next) {
  someAsyncIo(function(err) {
    if (err) return next(err);
    res.status(200).json({message: 'ok'});
  });
});

res.on('end', function() {
  console.log('end was called');
  process.exit(0);
});

router.handle(req, res, function() {});