process.kt

private val targets = mutableListOf<KSClassDeclaration>()

override fun process(resolver: Resolver): List<KSAnnotated> {
    // read @JsonClass annoted class
    val symbols = resolver.getSymbolsWithAnnotation("com.squareup.moshi.JsonClass")

    symbols.filter { ksAnnotated ->
            // only filter out class.
            ksAnnotated is KSClassDeclaration && ksAnnotated.validate()
        }
        .forEach { kSClassDeclaration ->
            // look browse class information via CustomKSVisitor
            kSClassDeclaration.accept(CustomKSVisitor(targets), Unit)
        }

    return emptyList()
}