class PeriodicGenerator {

    PeriodicGenerator(Observable<T> sourceObservable,
                      long initialDelay,
                      long interval,
                      TimeUnit timeUnit,
                      Scheduler scheduler) {
        this.sourceObservable = sourceObservable;
        this.scheduler = scheduler;
        this.initialDelayMs = timeUnit.toMillis(initialDelay);
        this.intervalMs = timeUnit.toMillis(interval);
    }

      PeriodicGenerator(Observable<T> sourceObservable,
                      long initialDelay,
                      long interval,
                      TimeUnit timeUnit,
                      Scheduler scheduler);

}