[ref] Go router

[at15]

• default mutex from net/http is relatively week
• https://github.com/julienschmidt/go-http-routing-benchmark by author of httprouter
• https://github.com/julienschmidt/httprouter use a radix tree and seems to be the fastest
• I was mainly using https://github.com/gorilla/mux which has a god sub router feature

In fact

• for simple routes ... a hard coded router might also work .... if strings.StartWith

[at15]

so far using default mux is enough ... and we didn't enforce what router user should use, router itself is just
a http handler