Swift 优雅的定时器及执行工具库 Each

• 完全可配置的定时器   
• 支持以毫秒，秒，分和小时为单位的时间间隔   
• 完全可扩展   
• 与NSTimer对象相比，使用起来更加可读和简单

let timer = Each(1).seconds     // Can be .milliseconds, .seconds, .minute, .hours  

timer.perform {
    // Do your operations
    // This closure has to return a NextStep value
    // Return .continue if you want to leave the timer active, otherwise
    // return .stop to invalidate it
}

timer.stop()    // This stops immediately the timer

timer.restart()