public void TakeErrorTest()
{
var subject = new Subject<string>();
var result = new List<IValueOrError<string>>();
subject
.TakeError()
.Subscribe(result.Add);
subject.OnNext("a");
subject.OnError(new Exception("error!"));
result.Count.Is(2);
result[0].IsError.IsFalse();
result[1].IsError.IsTrue();
}