Redis broker bypasses AMQP-style prefetch backpressure

Redis broker doesn't respect prefetch count on a consumer basis like AMQP does. AMQP won't send more messages when prefetch limit is reached until messages are ack/nack'd, but Redis broker continues sending messages. This makes Redis broker more susceptible to work_queue overflow under load.

When using Redis broker with large queues, implement explicit work_queue size limits. Monitor in-progress message counts and adjust prefetch settings conservatively. Consider AMQP broker if automatic backpressure behavior is required.