Webhook Consumer Implementation

Help me implement a reliable webhook consumer for events from {{source}} in {{stack}}. Cover verifying the signature for security, responding fast and processing async so you do not time out, idempotency to handle duplicate deliveries safely, handling out-of-order events, retries and what to do with failures, and logging for debugging. Note that webhook providers retry and may deliver duplicates or out of order, so processing must be idempotent, and flag the mistakes that cause missed or double-processed events.