gw-03 — References

The Zuul lineage (read these closely)

Netflix/zuul (GitHub) — the open-source gateway. Read the filter interfaces (ZuulFilter, HttpInboundFilter, HttpOutboundFilter, HttpInboundSyncFilter), SessionContext, and the Netty ChannelHandler pipeline. https://github.com/Netflix/zuul
Zuul 2: The Netflix Journey to Asynchronous, Non-Blocking Systems — the blocking→event-loop rationale; ~25% throughput/CPU win. https://netflixtechblog.com/zuul-2-the-netflix-journey-to-asynchronous-non-blocking-systems-45947377fb5c
Open Sourcing Zuul 2 — architecture overview, the filter phases, the 80+ clusters / 1M+ rps scale. https://netflixtechblog.com/open-sourcing-zuul-2-82ea476cb2b3
Zuul wiki — filter types, push messaging, request lifecycle. https://github.com/Netflix/zuul/wiki

Envoy http_connection_manager + HTTP filters — the C++ production twin of this lab; read one filter end to end (gw-08). https://www.envoyproxy.io/docs/envoy/latest/intro/arch_overview/http/http_filters
Spring Cloud Gateway — the JVM successor many teams use; same filter model, reactive (Project Reactor) instead of raw Netty.
Kubernetes Gateway API — the standardized routing CRDs (gw-10).
NGINX/OpenResty — the Lua-scriptable predecessor model.

Netty in Action — EventLoopGroup, ChannelPipeline, ChannelHandler, the "never block the event loop" rule.
ReactiveX / Project Reactor docs — the Observable/Mono/Flux model Zuul 2 and Spring Cloud Gateway use for async chains.
Go net/http ReverseProxy (net/http/httputil) — the stdlib reverse proxy this lab's Go version builds on; read ReverseProxy and Transport.

Upstream: gw-01 (acceptor/event loop), gw-02 (L7 decoding).
Downstream: gw-04 (endpoint-phase connection pool), gw-06 (endpoint-phase resilience), gw-07 (inbound security), gw-08 (control plane pushing routes), gw-11 (outbound observability), gw-12 (shipping filter changes safely).