ked whenever <a href="../dart-ui/Window/platformBrightness.html">platformBrightness</a> changes value. <a href="../dart-ui/Window/onPlatformBrightnessChanged.html">[...]</a>
                  <div class="features">read / write</div>
</dd>
        <dt id="onPlatformMessage" class="property">
          <span class="name"><a href="../dart-ui/Window/onPlatformMessage.html">onPlatformMessage</a></span>
          <span class="signature">&#8596; <a href="../dart-ui/PlatformMessageCallback.html">PlatformMessageCall