code: func Log(r *http.Request) *zap.Logger {
  	v := r.Context().Value(CtxLoggerKey)
  	log, ok := v.(*zap.Logger)
  	if !ok {
  		panic("cannot get derived request id logger from context object")
  	}
  	return log
  }
docs: // Log returns the Request ID scoped logger from the request Context
  // and panics if it cannot be found. This function is only ever used
  // by your controllers if your app uses the RequestID middlewares,
  // otherwise you should use the controller's receiver logger directly.