title: 'of' vs 'from' operator
body: <p>Is the only difference between <code>Observable.of</code> and <code>Observable.from</code> the arguments format? Like the <code>Function.prototype.call</code> and <code>Function.prototype.apply</code>?</p>
  
  <pre><code>Observable.of(1,2,3).subscribe(() =&gt; {})
  Observable.from([1,2,3]).subscribe(() =&gt; {})
  </code></pre>