public static IObservable <IList <TSource> > Buffer <TSource>(this IObservable <TSource> source, Func <TSource, int> sizeSelector, int maxSize, TimeSpan bufferTimeSpan)
{
BehaviorSubject <Unit> queue = new BehaviorSubject <Unit>(new Unit()); //our time-out mechanism
return(source
.Union(queue.Delay(bufferTimeSpan))
.ScanUnion(
(list: ImmutableList <TSource> .Empty, size: 0, emitValue: (ImmutableList <TSource>)null),
(state, item) => { // item handler
var itemSize = sizeSelector(item);
var newSize = state.size + itemSize;
if (newSize > maxSize)
{
queue.OnNext(Unit.Default);
return (ImmutableList <TSource> .Empty.Add(item), itemSize, state.list);
}
else
{
return (state.list.Add(item), newSize, null);
}
},
(state, _) => { // time out handler
queue.OnNext(Unit.Default);
return (ImmutableList <TSource> .Empty, 0, state.list);
}
)
.Where(t => t.emitValue != null)
.Select(t => t.emitValue.ToList()));
}
public static IObservable <TResult> IntervalAsync <TResult>(Func <IObservable <TResult> > f, TimeSpan period, IScheduler scheduler)
{
return(Observable.Create <TResult>(o =>
{
var q = new BehaviorSubject <TimeSpan>(TimeSpan.Zero);
var observable = q
.Delay(t => Observable.Timer(t))
.SelectMany(_ => f())
.Do(t => q.OnNext(period));
return observable.Subscribe(o);
}));
}