requestRedraw method
      
void
requestRedraw()
      
     
    
Requests a redraw of all dirty components.
Does nothing if a full recompute is already pending or app requests rebuild.
After redrawing dirty components, triggers a final render call.
Implementation
void requestRedraw() {
  if (needsRecompute || AppInstance.instance.shouldRebuild) return;
  for (var component in _dirtyComponents) {
    buffer.clearBufferArea(component.bounds);
    component.render(buffer, component.bounds);
  }
  _dirtyComponents.clear();
  render();
}