title: best practice typing an Observable event with no value
body: <p>I want to define a method returning an Observable but I don't have any data, what signature should I sue ?</p>
  
  <pre><code>myMethod(): Observable&lt;null&gt;;
  myMethod(): Observable&lt;void&gt;;
  myMethod(): Observable&lt;{}&gt;;
  </code></pre>
  
  <p>When coding the return in the method, I want to receive a next event in my first subscribe callback, so I can't use Observable.empty();</p>
  
  <p>I could use the following :</p>
  
  <pre><code>myMethod(): Observable&lt;null&gt;; //I could use  return Observable.of(null);
  myMethod(): Observable&lt;void&gt;; //I could use  return Observable.of(null);
  myMethod(): Observable&lt;{}&gt;; //I could use  return Observable.of({});
  </code></pre>
  
  <p>I did not find an official way of doing it, but maybe there's a standard solution ... What is the best practice ?</p>