union
fun Arguments.union(displayName: Key, description: Key, typeName: Key? = null, shouldThrow: Boolean = false, vararg converters: GenericConverter, validator: <Error class: unknown class><Any> = null): UnionConverter
Create a union converter, for combining other converters into a single argument - with the caveat of type erasure.
This function will automatically remove converters if they were previously registered, so you can use pass it the results of the usual extension functions.