Checkable Handler Holder
fun <I : O, O : State> CheckableHandlerHolder(inputKlass: KClass<I>, strict: Boolean = false, delegateTo: StatesHandler<I, O>): CustomizableHandlerHolder<O, O>
inline fun <I : O, O : State> CheckableHandlerHolder(strict: Boolean = false, delegateTo: StatesHandler<I, O>): CustomizableHandlerHolder<O, O>