Node.js HTTP Proxy: Layered Timeouts for CDN-Tunneled Origins

Problem

When proxying HTTP requests through a CDN tunnel (e.g., Cloudflare Tunnel / cloudflared), a simple connect timeout is useless because the CDN edge server is always reachable. If the origin behind the tunnel goes down (laptop sleeps, server crashes), the TCP+TLS handshake succeeds instantly against the CDN, but the request hangs for the full request timeout (often 30-60s) waiting for the CDN to forward through the dead tunnel.

With a circuit breaker that requires N failures to open, the worst case is N * request_timeout seconds of total hang time before fallback works.

Context / Trigger Conditions