 <span class="name"><a href="dart-ui/FrameCallback.html">FrameCallback</a></span><span class="signature">(<wbr><span class="parameter" id="FrameCallback-param-duration"><span class="type-annotation"><a href="dart-core/Duration-class.html">Duration</a></span> <span class="parameter-name">duration</span></span>)
            <span class="returntype parameter">&#8594; void</span>
          </span>
                  </dt>
        <dd>
          Signature for <a href="dart-ui/Window/onBeginFrame.html">Window.onBe