C# - language-level design patterns

Question

C# allows the Observer Pattern to be implemented via:

• The API: IObservable<T>, IObserver<T>
• The Language: Events & Delegates

Are there any other examples of design patterns that C# implements at the language level?

Answer 1

1. foreach loop and IEnumerable - is Iterator Pattern from GoF
2. C# events are basically an implementation of 'Chain of Responsibility'
3. Nullable<T> types like int? - are an example of Decorator pattern.

Not exactly a language level but still:

4. StringBuilder class is an example of GoF Builder pattern.
5. WPF ICommand - Command pattern from GoF