public void GivenObservingChange_WhenSettingChanged_ThenChangeObserved()
{
// Given
var result = 0;
SettingsProvider sut = new SettingsProviderFixture();
sut.Set(new Setting <int>(Key, 1));
sut.Observe <int>(Key).Subscribe(_ => result = _.Value);
// When
sut.Set(new Setting <int>(Key, 2));
// Then
result.Should().Be(2);
}
