ture feature-null-safety" title="Supports the null safety language feature.">Null safety</a>
</h1></div>

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    <li>@<a href="https://api.flutter.dev/flutter/dart-core/override-constant.html">override</a></li>
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<span class="returntype"><a href="https://api.flutter.dev/flutter/widgets/State-class.html">State</a><span class="signature">&lt;<wbr><span class="type-parameter"><a href="https://api.flutter.dev/flutt