SwiftでDispatchQueueでdebounce

debounce.swift

extension DispatchQueue {
    func debounce(interval: DispatchTimeInterval) -> (_ exec: @escaping () -> ()) -> DispatchSourceTimer? {
        var timer: DispatchSourceTimer?

        return { [weak self] exec in
            timer?.cancel()
            
            timer = DispatchSource.makeTimerSource(queue: self)
            timer?.setEventHandler(handler: exec)
            timer?.schedule(deadline: .now() + interval, repeating: .infinity)
            timer?.resume()

            return timer
        }
    }
}