Delay the execution of a given closure on the main queue

Delay.swift

public func delay(time: Double, completion: () -> Void) {
    let ms = dispatch_time(DISPATCH_TIME_NOW, Int64(time * Double(NSEC_PER_SEC)))
    dispatch_after(ms, dispatch_get_main_queue()) {
        () -> Void in
        completion()
    }
}

public func delay(time: Double) -> (()->Void) -> Void {
    return {
        (closure) -> Void in
        let ms = dispatch_time(DISPATCH_TIME_NOW, Int64(time * Double(NSEC_PER_SEC)))
        dispatch_after(ms, dispatch_get_main_queue()) {
            () -> Void in
            closure()
        }
    }
}