title: rxdart - using combineLatest, the way combiner works
body: <p>How does the combiner actually work?</p>
  <pre><code>Stream&lt;bool&gt; get isValid =&gt; Rx.combineLatest2(name1, mobile1, (name2, mobile2) =&gt; true);
  </code></pre>
  <p>If <code>name1</code> and <code>mobile1</code> are streams, then what are the types of <code>name2</code> and <code>mobile2</code> in brackets?</p>