code: func NewWithPrefix(ctx interface{}, pathPrefix string) *Router {
  	r := New(ctx)
  	r.pathPrefix = pathPrefix
  
  	return r
  }
docs: // NewWithPrefix returns a new router (see New) but each route will have an implicit prefix.
  // For instance, with pathPrefix = "/api/v2", all routes under this router will begin with "/api/v2".