title: Dart - What happened to File (dart:io) in Flutter 2.2
body: <p>I just upgraded to latest flutter version 2.2, and now this piece of code is not working.</p>
  <pre><code>import 'dart:io';  //this line is greyed out now
  .
  .
  file = File(&quot;${dir.path}/file.pdf&quot;); //error: Abstract classes can't be instantiated.
  </code></pre>
  <p>I checked the release notes, and could not locate any breaking changes regarding this. <a href="https://api.flutter.dev/flutter/dart-io/File-class.html" rel="nofollow noreferrer">The Documentaion</a> shows the File class as abstract, and still the example says:</p>
  <pre><code>var myFile = File('file.txt');
  </code></pre>
  <p>What should be the alternative to replace this line?</p>