delay(duration, index) → {Phaser.Tween}
Sets the delay in milliseconds before this tween will start. If there are child tweens it sets the delay before the first child starts.The delay is invoked as soon as you call Tween.start. If the tween is already running this method doesn't do anything for the current active tween.If you have not yet called Tween.to or Tween.from at least once then this method will do nothing, as there are no tweens to delay.If you have child tweens and pass -1 as the i