server.go
func NewServerMux() (mux *ServerMux) {
	nf := struct {
		View    view.View
		Handler HandlerFunc
	}{view.Simple(view.ContentTypePlain, view.CharSetUTF8), defaultNotFound}
	return &ServerMux{NewRouters(), nil, nil, nil, nf}
}
func NewServerMux() (mux *ServerMux) {
	nf := struct {
		View    view.View
		Handler HandlerFunc
	}{view.Simple(view.ContentTypePlain, view.CharSetUTF8), defaultNotFound}
	return &ServerMux{NewRouters(), nil, nil, nil, nf}
}
// NewServerMux returns a new Handler.