What's a good intuition for when to design something as a service? I understand the general concept of a web service but none of the examples in the documentation involve an HTTP server so "Service" is clearly an abstraction, but what are the boundaries of the analogy? I see a RNG as a service in the documentation, does that mean that managing internal state is part of what makes something a good candidate to be a service? I see the provision of services via Context in the documentation, does that mean that anything passed as a dependency is a good candidate to be a service?