Fake scrapy or how to build a scrapy like to learn
Distinguish request;Request for yield and client.Response for return add callback In Request
asyncio + aiohttp
asyncio.queue asyncio.semaphore asyncio.event https://www.roguelynn.com/words/asyncio-graceful-shutdowns/
Item class Request class Scheduler class
https://docs.python.org/3/library/asyncio-stream.html#asyncio-streams