Ref: [OpenAPI Specification 3.1.0 - Composition and Inheritance (Polymorphism)](https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.1.0.md#composition-and-inheritance-polymorphism) Current Mocker ignores `allOf` property, so it's not possible to use composition in models. Mocker should merge components joined by `allOf` refs.