Reproducer for unexpected EOFs with "httputil: ReverseProxy read error during body copy: read tcp 127.0.0.1:41980->127.0.0.1:8080: use of closed network connection" logs in queue-proxy.

• Set GOPATH
• Install ko (Makefile expect ${GOPATH}/bin/ko to exist)
• make apply-receiver-ksvc
• wait a bit
• make apply-sender-ksvc
• Watch logs for the error:
  • kubectl logs -n sender-ksvc -l serving.knative.dev/service=sender-ksvc -c user-container -f
  • kubectl logs -n receiver-ksvc -l serving.knative.dev/service=receiver-ksvc -c queue-proxy -f | grep httputil
• After a while, notice the errors (maybe)
  • httputil: ReverseProxy read error during body copy: read tcp 127.0.0.1:60188->127.0.0.1:8080: use of closed network connection in receiver queue-proxy logs
  • error reading body: unexpected EOF in sender logs

There are also make apply-receiver-k8s and make apply-sender-k8s variants which use plain k8s Deployments and don't manifest the errors.