Add test C.4 from spec
Add test C.4 from spec

cmars/tools,cmars/tools,raboof/net,DramaFever/golang.org-x-net,cmars/tools,raboof/net,golang/net,cmars/tools,DramaFever/golang.org-x-net,cesanta/goxnet,gomini/net,albertjin/golang-net,cesanta/goxnet,gomini/net,albertjin/golang-net