Feature: Using Java classes as schemas

Occasionally, it is necessary to drop down to Java interop. When that happens, I don't want to lose the ease and simplicity of Malli's validation, and I don't want to have to write my own custom :fn schema each time merely to call (instance? SomeClass value).

It would be helpful to have support for recognizing Java classes, effectively wrapping instance? for general use. I looked at the malli.core code and I'm not entirely sure how to accomplish this or I'd offer to do it.

Thanks so much