What problem does it solve? Adding a new message queue backend to funboost requires implementing abstract Publisher and Consumer classes and registering them correctly, which is error-prone without guidance on the framework's extension contracts. ## Core Features & Use Cases - Three Extension Paths: Covers static extension for framework authors, register_custom_broker for user-space brokers, and consumer_override_cls/publisher_override_cls mixins for customizing existing brokers. - Implementation Contracts: Documents the required abstract methods (_publish_impl, clear, get_message_count, close, _dispatch_task, _confirm_consume, _requeue), the kw dictionary structure, and super() call rules. - Use Case: You need funboost to consume tasks from an in-house message queue. Implement a custom Publisher and Consumer subclass, register them with register_custom_broker, and use the new broker_kind in BoosterParams. ## Quick Start Ask the AI to implement a custom funboost broker for your message queue by subclassing AbstractPublisher and AbstractConsumer and registering it with register_custom_broker.