private
    var closed = false

    fun type(sourceName: String): ApiType? = open {
        apiTypesBySourceName.computeIfAbsent(sourceName) {
            repository.classBytesFor(sourceName)?.let { apiTypeFor(sourceName) { it } }
        }?.invoke()
    }

    internal
    fun allTypes(): Sequence<ApiType> = open {
        repository.allClassesBytesBySourceName().map { (sourceName, classBytes) ->