如何理解python中的aiohttp库

import time
 
import asyncio
import aiohttp
 
 
async def get_html():
    async with aiohttp.request('GET', "https://open.163.com/") as res:
        return await res.text()
 
 
async def main():
    tasks = [asyncio.ensure_future(get_html()) for i in range(20)]
 
    dones, pendings = await asyncio.wait(tasks)
    for task in dones:
        print(len(task.result()))
 
 
if __name__ == '__main__':
    start_time = time.perf_counter()
    asyncio.run(main())
    print("aiohttp 异步采集消耗时间为：", time.perf_counter() - start_time)
    # aiohttp 异步采集消耗时间为： 0.275251032