This is more a feature request then a issue.

I've read quite a few issues here about users trying to accomplish external api calls as part of their validation process so I'm just "formalising" the request here.

So to give some context... the issue is with the Joi.extend API. The method rules.validate expect me to return something immediately.

Would be fantastic if it could handle a Promise as a return and still respect the method chain.

Thanks and let me know if I can provide more insights about this.