title: Observable vs Subject and asObservable
body: <p><strong>I am learning RxJs, I am seeking confirmation or correction on my assumption.</strong></p>
  
  <p>I am trying to make a <em>public read only</em> observable in a service that I can use <code>.next()</code> on in various places in my service class. I am wondering if this is the proper way to do it:</p>
  
  <pre><code>private myObservable = new Subject&lt;T&gt;();
  public myObservable$: Observable&lt;T&gt; = this.myObservable.asObservable();
  </code></pre>
  
  <ul>
  <li>The user can subscribe to <code>myObservable$</code></li>
  <li>I can use<code>myObservable.next(...);</code></li>
  </ul>
  
  <p>It works perfectly but I am experience enough to know that I may just be being an unwitting idiot (RxJS is huge). Is this correct pattern and correct object for said use case?</p>