title: Difference between 'new BehaviorSubject' and 'BehaviorSubject.create'
body: <p>I am using Angular 2 and RxJS 5.</p>
  
  <p>Is there any difference between these two:</p>
  
  <p>And which should be used first? Thanks</p>
  
  <pre><code>isOpen$ = new BehaviorSubject&lt;boolean&gt;(true);
  </code></pre>
  
  <p>and</p>
  
  <pre><code>isOpen$ = BehaviorSubject.create(true);
  </code></pre>