public void ToDictionary_Get()
 {
     var source = new ObservableDictionary<int, string>();
     var get2 = Nothing<string>();
     source.ToLiveLinq()[2].Subscribe(val => get2 = val);
     get2.Should().Be(Nothing<string>());
     source.Add(2, "Hi there");
     get2.Should().Be(Something("Hi there"));
 }