title: rxjs - what is the difference from result perspective to do actions in .do() and .subscribe()
body: <p>For examples, I have the following code that I can write in two ways:</p>
  
  <pre><code>1. 
  ObsevableA.do(() =&gt; { 
     doSomething();
  })
  .subscribe();
  
  2.
  ObservableA.subscribe(() =&gt; {
    doSomething();
  });
  </code></pre>
  
  <p>The end result seems to be the same. Any thoughts on each approach? What is the best practice I should be using? Thanks.</p>