System.Reactive.Linq.ObservableImpl.GroupByUntil<TSource, TKey, TElement, TDuration>
sealed class GroupByUntil<TSource, TKey, TElement, TDuration> : Producer<IGroupedObservable<TKey, TElement>, _<TSource, TKey, TElement, TDuration>>
namespace System.Reactive.Linq.ObservableImpl
{
}