title: what this scala symbol ->_ means
body: <p>can someone assist me understanding this code </p>
  
  <pre><code>case "Foo" Foo(data) -&gt; _ =&gt; { /*.. implementation */}
  </code></pre>
  
  <p>I see the usage of Foo.unapply(data) 
  but I don't understand what this part </p>
  
  <blockquote>
    <p>-> _</p>
  </blockquote>
  
  <p>how and when to use it  </p>