Restify next(err) don't serialize extraneous options created by makeConstructor

When sending error with next(error) callback, response sent to client does not contain optionnal properties of my new Error Object created with makeConstructor restify-errors module.

Env : Node v12.18.3 with ESM loader (type: "module") in package.json

Example :

import errs from 'restify-errors';
const TestError = errs.makeConstructor("TestError", {
   statusCode: 500, 
   info: {errcode: "ERR_GENERIC"},
   message:"App Error"
});
const tmp = new TestError();
console.log("tmp.info exists : ", JSON.stringify(tmp.info)); 
console.log("But this is sent to client when next(tmp) called : ", JSON.stringify(tmp)); 

Print :

tmp.info exists : {"errcode":"ERR_GENERIC"}
But this is sent to client when next(tmp) called : {"code":"Test","message":"App Error"}

It seems to be caused by JSON.stringify that only check for ownProperties (it don't look for prototype chain).

Start with errs.makeConstructor and the next(error) serialization path described in the example; compare the constructed error's properties with its JSON.stringify output. Reproduce the Node v12.18.3 ESM case, then add a focused test showing that optional constructor properties such as info are included in the serialized response.