Selgitage Cold kontseptsiooni Swiftis Combine'i kasutamise kontekstis.

In Swift's Combine framework, the concept of Cold Publisher means that the publisher does not start generating and sending values until a subscriber subscribes.

This means each subscriber receives its own data stream from the moment of subscription, and data is not pre-generated.

Example:

let publisher = [1, 2, 3].publisher // Cold publisher

publisher.sink { print("Subscriber 1 received: \($0)") }
publisher.sink { print("Subscriber 2 received: \($0)") }

In this example, both subscribers will receive all values from the beginning, because the publisher is "cold" and only starts emitting data when someone subscribes.