Don't manage to concat an observable with a hot observable, with buffering the 2nd one while the 1st is actually working

rx-test-FIXED.js

'use strict';

var Rx = require('rx');
var EventEmitter = require('events').EventEmitter;

var emitter = new EventEmitter();

var observable1 = new Rx.Subject();
var buffer = new Rx.ReplaySubject();
var observable2 = Rx.Observable.fromEvent(emitter, 'test');
observable2.subscribe(buffer);

emitter.emit('test', {a: 1});
emitter.emit('test', {a: 2});

observable1.concat(buffer)
  .subscribe(e => {
    console.log('concat', e);
  });

observable1.onNext({b:3});
observable1.onNext({b:4});
observable1.onCompleted();

rx-test.js

'use strict';

var Rx = require('rx');
var EventEmitter = require('events');

var emitter = new EventEmitter();

var observable1 = new Rx.Subject();
var controller = new Rx.Subject();
var observable2 = Rx.Observable.fromEvent(emitter, 'test')
  .pausableBuffered(controller);

emitter.emit('test', { a: 1 });
emitter.emit('test', { a: 2 });

observable1.doOnCompleted(() => {
  controller.onNext(true);
});

observable1.concat(observable2)
  .subscribe(e => {
    console.log(e);
  });

observable1.onNext({b:3});
observable1.onNext({b:4});
observable1.onCompleted();

I expect this code to output

{b:3}
{b:4}
{a:1}
{a:2}

But I don't manage to get observable2 values in the concat...
Any way to fix this ?

@rehia change line 16 from

observable1.doOnCompleted(() => {
  controller.onNext(true);
});

to

observable1.subscribe(null, null, () => {
  controller.onNext(true);
});

Or L20 from

observable1.concat(observable2)

to

observable1.doOnCompleted(() => controller.onNext(true)).concat(observable2);

then remove L16-18

@d6u @trcllnt Thanks for your suggestion.
But I didn't manage to make it work with it... :( Event after fixing line 4 issue (missing EventEmitter).
I followed the advice I got on a tweet, and it did the job !
https://twitter.com/yermakavets/status/702247545985228800
I put my solution in a FIXED version of the original file.

Node version is 4.3.1, Rx 4.0.8 (if it can help)