static IObservable <Unit> SendAction(this RestActionOperationAttribute attribute, SimpleAction action)
=> action.WhenExecute().SelectMany(t1 => t1.SelectedObjects.Cast <object>().ToObservable()
.SelectMany(instance => attribute.Send(instance, t1.Action.Application
.GetCurrentUser <ICredentialBearer>()))).ToUnit();
static IObservable <Unit> SendAction(this IEnumerable <object> source, RestActionOperationAttribute attribute, SimpleAction action)
=> source.ToObservable().SelectMany(instance => attribute.Send(instance, action.Application
.GetCurrentUser <ICredentialBearer>())).ToUnit();
