e pre-defined constants to write the above
in the following way:</p>
<pre class="language-dart"><code>new Observable.fromIterable([1, "hi"])
  .ofType(kString)
  .listen(print); // prints "hi"
</code></pre>
<p>If you'd like to create your own shortcuts like the example above,
simply create a constant:</p>
<pre class="language-dart"><code>const TypeToken&lt;Map&lt;Int, String&gt;&gt; kMapIntString =
  const TypeToken&lt;Map&lt;Int, String&gt;&gt;();
</code></pre>
    </section>
    
    <section class="summa