This method is called by the RenderLoop where this Stage is added to. If this Stage is not added to a RenderLoop you could call this method on your own and therefore get full control of the rendering of this Stage.
Source
void materialize(num currentTime, num deltaTime) {
if (_stageRenderMode == StageRenderMode.AUTO ||
_stageRenderMode == StageRenderMode.ONCE) {
_updateCanvasSize();
_renderContext.reset();
_renderContext.renderStatistics.reset();
_renderContext.clear(backgroundColor);
_renderState.reset(_stageTransformation);
_renderState.currentTime = ensureNum(currentTime);
_renderState.deltaTime = ensureNum(deltaTime);
_renderState.renderObject(this);
_renderState.flush();
if (_stageRenderMode == StageRenderMode.ONCE) {
_stageRenderMode = StageRenderMode.STOP;
}
}
}