Timer. 一个倒计时类，除了可以开始取消倒计时，还可以暂停恢复倒计时，虽说时间一去不复返，我丫停停它总可以吧！啊哈哈

Problem

The full read on this project is a sign-in away — what it solves, who it serves, and where it sits in the market.

Audience

The full read on this project is a sign-in away — what it solves, who it serves, and where it sits in the market.

Market

The full read on this project is a sign-in away — what it solves, who it serves, and where it sits in the market.

Pricing

The full read on this project is a sign-in away — what it solves, who it serves, and where it sits in the market.