code: func (s *Server) InstallHandlers(r *router.Router, base router.MiddlewareChain) {
  	s.mu.Lock()
  	defer s.mu.Unlock()
  
  	rr := r.Subrouter("/prpc/:service/:method")
  	rr.Use(base.Extend(s.authenticate()))
  
  	rr.POST("", router.MiddlewareChain{}, s.handlePOST)
  	rr.OPTIONS("", router.MiddlewareChain{}, s.handleOPTIONS)
  }
docs: // InstallHandlers installs HTTP handlers at /prpc/:service/:method.
  //
  // See https://godoc.org/go.chromium.org/luci/grpc/prpc#hdr-Protocol
  // for pRPC protocol.
  //
  // The authenticator in 'base' is always replaced by pRPC specific one. For more
  // details about the authentication see Server.Authenticator doc.