cene</a>. This function must be called within the scope of the
<a href="../dart-ui/Window/onBeginFrame.html">onBeginFrame</a> or <a href="../dart-ui/Window/onDrawFrame.html">onDrawFrame</a> callbacks being invoked. If this function
is called a second time during a single <a href="../dart-ui/Window/onBeginFrame.html">onBeginFrame</a>/<a href="../dart-ui/Window/onDrawFrame.html">onDrawFrame</a>
callback sequence or called outside the scope of those callbacks, the call
will be ignored. <a href="../dart-ui/Wind