r><span class="type-parameter">R</span>&gt;</span> typedef </h1></div>

    <section class="multi-line-signature">
        <span class="returntype">R</span>
                <span class="name ">ZoneCallback</span>
(<wbr>)
    </section>

        <section class="summary source-code" id="source">
      <h2><span>Implementation</span></h2>
      <pre class="language-dart"><code class="language-dart">typedef R ZoneCallback&lt;R&gt;();</code></pre>
    </section>

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