llback</a> do the bare minimum required of the
function, and are only provided as a hook for custom zones. Others, like
<a href="dart-async/Zone/scheduleMicrotask.html">scheduleMicrotask</a>, interact with the underlying system to implement the
desired behavior.</p>
    </section>
        <section class="summary source-code" id="source">
      <h2><span>Implementation</span></h2>
      <pre class="language-dart"><code class="language-dart">static const Zone root = _rootZone

</code></pre>
    </section>

  