public static void TestAlwaysLast()
{
ISubject <int> subject = new BehaviorSubject <int>(1);// default value
subject.AttachConsoleHandlers();
Helper.Pause();
subject.OnNext(3);// different from AsyncSubject, data is published out even the stream is not completed
subject.AttachConsoleHandlers();
Helper.Pause();
subject.OnCompleted();
}