Asynchronious input validator

At the moment the input validator callback does not handle asynchronous function https://www.wix.com/corvid/reference/$w/textinput/oncustomvalidation

Let say you have a registration form and you want to validate an email input by checking if the email is already used or not. It's extremely complex to implement such a feature at the moment.

There are many use case where the validation relies on some kind of asynchronous code.

I would like that if validator callback returns a promise the input is disabled when the promise is pending. If the promise rejects the validation state is false and error is the reason. If the promise is resolve the validation state is true