<section class="multi-line-signature">
          Key?
          <span class="name ">key</span>
          <div class="features">final, inherited</div>

        </section>
        
<section class="desc markdown">
  <p>Controls how one widget replaces another widget in the tree.</p>
<p>If the <a href="https://api.dart.dev/stable/2.15.1/dart-core/Object/runtimeType.html">runtimeType</a> and <a href="../../textfield_search/TextFieldSearch/key.html">key</a> properties of the two widgets are
<a href="../../textfie