firstFrameRasterized property Null safety
Whether the Flutter engine has rasterized the first frame.
Usually, the time that a frame is rasterized is very close to the time that it gets presented on the display. Specifically, rasterization is the last expensive phase of a frame that's still in Flutter's control.
- waitUntilFirstFrameRasterized, the future when firstFrameRasterized becomes true.
bool get firstFrameRasterized => _firstFrameCompleter.isCompleted;