Get next event in sequence every second with reactive-extensions

Question

I have the below types ...

public class NewsFeed
{
    public event EventHandler NewItem;

    .....

}

public class NewsItemEventA         


        

Answer 1

Zip might not be the best choice for this operation because there's a chance for the producer to be slow at times, resulting a jittery output.

It seems accurate scheduling with DateTimeOffset still isn't possible with Rx 2.0. TimeSpan works for now, though. You can try it by replacing the TimeSpan offset with a DateTimeOffset.

In summary, if we can specify a minimum interval between two consecutive values, we can solve the burst problem.

    static IObservable DelayBetweenValues(this IObservable observable, TimeSpan interval, IScheduler scheduler)
    {
        return Observable.Create(observer =>
        {
            var offset = TimeSpan.Zero;
            return observable
                .TimeInterval(scheduler)
                .Subscribe
                (
                    ts =>
                    {
                        if (ts.Interval < interval)
                        {
                            offset = offset.Add(interval);
                            scheduler.Schedule(offset, () => observer.OnNext(ts.Value));
                        }
                        else
                        {
                            offset = TimeSpan.Zero;
                            observer.OnNext(ts.Value);
                        }
                    }
                );
        });
    }

Test:

        Observable.Interval(TimeSpan.FromSeconds(2.5))
                  .Do(_ => Console.WriteLine("Burst"))
                  .SelectMany(i => Enumerable.Range((int)i, 10))
                  .DelayBetweenValues(TimeSpan.FromSeconds(0.2), TaskPoolScheduler.Default)
                  .Subscribe(Console.WriteLine);