Scheduled NSTimer with a Swift closure

NSTimer+Closure.swift

extension NSTimer {
    /**
    Creates and schedules a one-time `NSTimer` instance.
    
    - Parameters:
        - delay: The delay before execution.
        - handler: A closure to execute after `delay`.
    
    - Returns: The newly-created `NSTimer` instance.
    */
    class func schedule(delay delay: NSTimeInterval, handler: NSTimer! -> Void) -> NSTimer {
        let fireDate = delay + CFAbsoluteTimeGetCurrent()
        let timer = CFRunLoopTimerCreateWithHandler(kCFAllocatorDefault, fireDate, 0, 0, 0, handler)
        CFRunLoopAddTimer(CFRunLoopGetCurrent(), timer, kCFRunLoopCommonModes)
        return timer
    }
    
    /**
    Creates and schedules a repeating `NSTimer` instance.
    
    - Parameters:
        - repeatInterval: The interval (in seconds) between each execution of
          `handler`. Note that individual calls may be delayed; subsequent calls
          to `handler` will be based on the time the timer was created.
        - handler: A closure to execute at each `repeatInterval`.
    
    - Returns: The newly-created `NSTimer` instance.
    */
    class func schedule(repeatInterval interval: NSTimeInterval, handler: NSTimer! -> Void) -> NSTimer {
        let fireDate = interval + CFAbsoluteTimeGetCurrent()
        let timer = CFRunLoopTimerCreateWithHandler(kCFAllocatorDefault, fireDate, interval, 0, 0, handler)
        CFRunLoopAddTimer(CFRunLoopGetCurrent(), timer, kCFRunLoopCommonModes)
        return timer
    }
}

// Usage:
var count = 0
NSTimer.schedule(repeatInterval: 1) { timer in
    print(++count)
    if count >= 10 {
        timer.invalidate()
    }
}

NSTimer.schedule(delay: 5) { timer in
    print("5 seconds")
}