title: How to operate with PublishSubject as with Observable
body: <p>I have a PublishSubject:</p>
  
  <pre><code>PublishSubject&lt;MyEvent&gt; subject = PublishSubject.create();
  </code></pre>
  
  <p>And I need to get internal Observable and perform some actions on it. 
  Simple case for now(the code is broken because doOnNext return <code>Observable</code> and I need <code>Subject</code>):</p>
  
  <pre><code>PublishSubject.create().doOnNext(new Action1&lt;MyEvent&gt;() {
          @Override
          public void call(MyEvent o) {
              System.out.println("my event:"+o);
          }
      }));
  </code></pre>
  
  <p>I see two ways to do this.
  First is - create own subscriber and create PublishSubject based on it.
  Second - merge internal subscriber with own.</p>
  
  <p>But I don't know how to implement any of these methods.</p>