title: Update assets files content at runtime with Flutter
body: <p>I am fresh with Flutter, and I was able to load the content of XML file as String from Assets folder using this method</p>
  
  <pre><code>Future&lt;String&gt; loadAsset() async {
      return await rootBundle.loadString('assets/file.xml');
  }
  </code></pre>
  
  <p>and yaml file</p>
  
  <pre><code>flutter:
     assets:
        - assets/
  </code></pre>
  
  <p>And it just works very well.</p>
  
  <p><strong>My question is:</strong> Can I update an attribute value or add some nodes to my XML file and save it on the same place at Assets folder at <strong>Runtime</strong> of Flutter app?</p>
  
  <blockquote>
    <p>In sentence: I want to install the application on the user's device with original file of XML and user can modify it at any time as long as the application installed.</p>
  </blockquote>