What is a Kotlin `suspend` function and how does it work?

This question tests your fundamental grasp of how Kotlin coroutines achieve non-blocking concurrency. A strong answer defines a `suspend` function as one that can be paused and resumed without blocking a thread. It then states the two key rules: it can only be called from another suspend function or a coroutine builder. Finally, it explains that the compiler implements this via Continuation-Passing Style (CPS), adding a hidden `Continuation` parameter to manage state. A common mistake is equating `suspend` with thread blocking.