System.Reactive.Linq.ObservableImpl.GroupByUntil<TSource, TKey, TElement, TDuration> sealed class GroupByUntil<TSource, TKey, TElement, TDuration> : Producer<IGroupedObservable<TKey, TElement>, _<TSource, TKey, TElement, TDuration>> Documentation Code public GroupByUntil(IObservable<TSource> source, Func<TSource, TKey> keySelector, Func<TSource, TElement> elementSelector, Func<IGroupedObservable<TKey, TElement>, IObservable<TDuration>> durationSelector, int? capacity, IEqualityComparer<TKey> comparer)