public bool OnFrameRenderingQueued()
{
// Increment next frame number
NextFrameNumber++;
long now = this.timer.Milliseconds;
frameEventArgs.TimeSinceLastFrame = this.CalculateEventTime( now, FrameEventType.Queued );
// if any event handler set this to true, that will signal the engine to shutdown
return this.OnFrameRenderingQueued( frameEventArgs );
}