where use the request_cls, response_cls?

Nice catch, forgot to use them in code. Will make another commit now.

self.response_cls

this is already used. when translating response.

add_spiders() -> empty?!
where are the spiders to add?

we define them in the chain

async def main():
    process = Process(
        spider=MySpider() >> MySpiderTwo() >> MySpiderThree(),
        cond="every 1 second",
        controller=ProcessController(app=RocketryApplication()),
    )
    await process.add_spiders()

the method add_spiders also adds them to the controller, if there's any defined.
it is not meant to be called like this, usually this happen underhood in FastCrawler App. but if a user want to initiate and run a process manually, that's the way to go.