HTTP Cache

HTTPX has no in-memory HTTP cache subsystem. HTTP caching is handled where it is actually implemented:

• Static files: server.static(mount, dir) serves with ETags and honors If-None-Match (304 Not Modified). See examples/staticFiles.zig.
• Downloads: .existing = .verifyExisting skips re-downloads, and .replaceIfChanged uses conditional headers. See examples/downloadExisting.zig.
• DNS: client-side cache via ClientConfig.dnsCache.

Checklist

• [x] ETag generation and matching on static routes
• [x] Conditional GET (304 Not Modified)
• [x] Download resume and existing-file policies