Is your feature request related to a problem? Please describe.
From the docs, it looks like there's only an option to override a synchronous Validate method. There are many cases where it would be convenient to have async validation available by overriding a ValidateAsync method.
Describe the solution you'd like
Ideally, users of this library could override a Validate or ValidateAsync method, depending on their need for asynchrony during validation.
Describe alternatives you've considered
One alternative would be to use some of the strategies mentioned in this article to make async calls within a synchronous method. Each option listed there unfortunately does have drawbacks, though.
Additional context N/A
Please upvote :+1: this issue if you are interested in it.