Combine operator that mimics RxSwift's throttle when latest: false

Combine+Cooldown.swift

extension Publisher {
    func coolDown<S: Scheduler>(for cooltime: S.SchedulerTimeType.Stride,
                                scheduler: S) -> some Publisher<Self.Output, Self.Failure> {
        return self.receive(on: scheduler)
            .scan((S.SchedulerTimeType?.none, Self.Output?.none)) {
                let eventTime = scheduler.now
                let minimumTolerance = scheduler.minimumTolerance
                guard let lastSentTime = $0.0 else {
                    return (eventTime, $1)
                }
                
                let diff = lastSentTime.distance(to: eventTime)
                
                guard diff >= (cooltime - minimumTolerance) else {
                    return (lastSentTime, nil)
                }
                
                return (eventTime, $1)
            }
            .compactMap { $0.1 }
    }
}