title: This application cannot tree shake icons fonts
body: <p>While trying to build my app in release mode I encountered the following the compiler error:<br />
  &quot;This application cannot tree shake icons fonts.&quot;</p>
  <p>terminal logs:</p>
  <pre><code>flutter build ios --release  
  Building com.xxx.xxx for device (ios-release)...
  Automatically signing iOS for device deployment using specified development team in Xcode project: C7T4CHU88Y
  Running Xcode build...                                                  
                                                     
  Xcode build done.                                           31.8s
  Failed to build iOS app
  Error output from Xcode build:
  ↳
      ** BUILD FAILED **
  
  
  Xcode's output:
  ↳
      This application cannot tree shake icons fonts. It has non-constant instances of IconData at the following locations:
        - file:///Users/user-app/lib/screens/categories/subcategories.dart:830:35
        - file:///Users/user-app/lib/screens/home/home.dart:387:17
        - file:///Users/user-app/lib/screens/home/home.dart:399:17
        - file:///Users/user-app/lib/screens/home/home.dart:411:17
        - file:///Users/user-app/lib/screens/home/home.dart:423:17
        - file:///Users/user-app/lib/screens/product/all_products.dart:516:31
        - file:///Users/user-app/lib/screens/tab/saveditems.dart:324:31
        - file:///Users/user-app/lib/screens/tab/searchitem.dart:496:31
  </code></pre>
  <p>The error could result from the following file:</p>
  <pre><code>Column(
    children: &lt;Widget&gt;[
      Row(
        children: &lt;Widget&gt;[
          new Text(
            MyLocalizations.of(context).goToCart,
            style: textBarlowRegularBlack(),
          ),
          SizedBox(width: 4),
          Icon(
            IconData(
              0xe911,
              fontFamily: 'icomoon',
            ),
            color: Colors.black,
          ),
        ],
      ),
    ],
  ),
  </code></pre>