title: How to create subject ( rx.js) with 2 parameters?
body: <p>I am using service with subject as communication service for components in my angular2 application.</p>
  
  <p>Calling method:</p>
  
  <pre><code>this.notification.create('test');
  </code></pre>
  
  <p>Service: </p>
  
  <pre><code>export class NotificationService {
    private static notificationSource = new Subject&lt;any&gt;()
  
    notiCreated$ = NotificationService.notificationSource.asObservable();
  
    create(message) {
      NotificationService.notificationSource.next(message);
    }
  }
  </code></pre>
  
  <p>Called function:</p>
  
  <pre><code>  this.subscription = notification.notiCreated$.subscribe(
      data =&gt; {
         console.log(data);
         this.createNotification(data, 'warning');
    });
  </code></pre>
  
  <p>But I want to pass 2 params. And I got errors.</p>
  
  <p>How can i do it?</p>