public static IAsyncEnumerable <long> TimerAsync(this IMomentClock clock, long delayInMilliseconds) => clock.Timer(delayInMilliseconds).ToAsyncEnumerable();
public static IAsyncEnumerable <long> TimerAsync(this IMomentClock clock, TimeSpan dueIn) => clock.Timer(dueIn).ToAsyncEnumerable();
public static IObservable <long> Timer(this IMomentClock clock, long delayInMilliseconds) => clock.Timer(TimeSpan.FromMilliseconds(delayInMilliseconds));