Make ExecRouteAgainst to work better and fix gorillamux and httprouter, remove of contextlinker policy it's useless now

Former-commit-id: 8d3501e6c490d630d3a4bec0c077dcd7d532242f

iris.go

@@ -340,6 +340,16 @@ func New(setters ...OptionSetter) *Framework {
 				if routerBuilder != nil {
 					// buid the router using user's selection build policy
 					s.Router.build(routerBuilder)
+
+					s.Router.repository.OnMethodChanged(func(route RouteInfo, oldMethod string) {
+						// set service not available temporarily until the router completes the building
+						// this won't take more than 100ms, but we want to inform the user.
+						s.Router.handler = ToNativeHandler(s, HandlerFunc(func(ctx *Context) {
+							ctx.EmitError(StatusServiceUnavailable)
+						}))
+						// Re-build the whole router if state changed (from offline to online state mostly)
+						s.Router.build(routerBuilder)
+					})
 				}
 			}
 		}})