title: How to pause Observable?
body: <p>I am working on my first Angular 2 product. I created this <code>Observable.timer</code> and then subscribed to it. It polls the server for data.</p>
  
  <p>How do I pause and unpause this?</p>
  
  <pre><code>  ngOnInit(): void {
      this.poll = Observable.timer(500,500).subscribe((t: any) =&gt; {
        this.request.getRackList(+this.global.zoneId).subscribe(
          incoming =&gt; this.import(incoming),
          err =&gt; { this.global.err(err) }
        );
      })
      this.canOpenClose = (this.global.mode === 2);
    }
  </code></pre>