官方的Tutorial
https://developer.apple.com/tutorials/swiftui/creating-a-watchos-app
WWDC
https://developer.apple.com/videos/play/wwdc2022/10133/
這個影片有说为什么拿掉 Watch Extension
https://developer.apple.com/videos/play/wwdc2021/10003/
告诉你 Watch 有多少资料通讯的方式
https://developer.apple.com/videos/play/wwdc2015/713
特別介紹 Watch Connectivity