ServiceWorkerGlobalScope：registration 属性
Baseline
Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since 2018年4月.
备注： 此特性仅在 Service Worker 中可用。
ServiceWorkerGlobalScope 接口的 registration 只读属性返回对 ServiceWorkerRegistration 对象（表示此服务工作线程的注册信息）的引用。