Registering private, third-party Kotlin classes

[esafak]

I've encountered the error

org.apache.fury.exception.InsecureException: class kotlin.time.InstantSerialized is not registered

because I'm using it in a data class, but I can't register it because it is private.

[chaokunyang]

You can invoke fory.getClassResolver().register(String) method for registration. Maybe we should expose this API to BaseFory class too

[esafak]

I'm using ThreadSafeFory, which extends BaseFory. I'll prepare a PR to expose this functionality in BaseFory so I can use it.