FileVisitorBuilder

val cleanVisitor = fileVisitor {
    onPreVisitDirectory { directory, _ ->
        if (directory.name == "build") {
            directory.deleteRecursively()
            FileVisitResult.SKIP_SUBTREE
        } else {
            FileVisitResult.CONTINUE
        }
    }

    onVisitFile { file, _ ->
        if (file.extension == "class") {
            file.deleteExisting()
        }
        FileVisitResult.CONTINUE
    }

    onVisitFileFailed { entry, _ ->
        Logger.warn("Could not traverse and clean $entry")
        FileVisitResult.CONTINUE
    }
}