https://javascript.plainenglish.io/react-native-getting-user-device-timezone-and-converting-utc-time-stamps-with-offset-697902d7803 https://dev.to/ugglr/react-native-getting-user-device-timezone-and-converting-utc-time-stamps-using-the-offset-3jh8 获取的是 utc 字符串，转换到用户的时区 https://day.js.org/docs/zh-CN/timezone/set-default-timezone
