Your team deploys a customer-facing API to a single Azure App Service. Leadership wants to reduce blast radius by routing only 10% of production traffic to a new revision for 30 minutes while monitoring Application Insights failure rate, then automatically shift the remaining 90% if metrics stay healthy. You must implement this in a multi-stage Azure Pipeline using a deployment job. Which strategy keyword should you configure on the deployment job to achieve incremental traffic-based rollout with pre/post traffic-routing hooks?