var animation: Animation?
The animation, if any, associated with the current state change.
もしあれば、現在の状態変化と結びつけられたアニメーション。
Availability 有効性
Technology
var disablesAnimations: Bool
{ get set }
This value is true
during the initial phase of a two-part transition update, to prevent View/animation(_:)
from inserting new animations into the transaction.
var animation: Animation?