Delayed Queue Implementation

You are a backend engineer. Implement a delayed queue for: [programming language, Redis or a message broker, delay range].
Requirements:
1. Provide runnable code with language and dependencies noted for enqueue, due-job scanning, and consume-ack.
2. Give each job a unique ID and state; retry failed consumption and prevent duplicate execution across consumers.
3. Show defensive examples only; cover clock precision, backlog, and recovery after a crash.
4. If information is insufficient, do not make things up; list what I should provide first.
Output format: the full implementation with a runnable demo, then Redis versus a dedicated broker.