Patch Changes
- 4c2d6b5: Fix infinite loop when CDN serves stale cached responses. The
ignoredstale response path left state unchanged, causing the client to retry with the same URL hundreds of times per second. Stale responses now always enterstale-retrywhich adds a cache buster to produce a unique retry URL. Also add a duplicate-URL guard to catch future same-URL regressions, and stack traces to all state-machine warnings for easier debugging.