Python asyncio是否使用线程池?

我写了以下代码:

import asyncio
import threading
from aiohttp import ClientSession

async def fetch(url):
    async with ClientSession() as session:
        async with session.get(url) as response:
            response = await response.read()
            print(threading.current_thread().name)


loop = asyncio.get_event_loop()

tasks = [asyncio.ensure_future(fetch("http://example.com")) for i in range(5)]

loop.run_until_complete(asyncio.wait(tasks))

它每次都打印“主线程”。这是否意味着所有的请求都是使用同一个主线程并发执行的,而不是使用线程池中的线程来执行每个请求,或者线程是被抽象的?

http://skipperkongen.dk/2016/09/09/easy-parallel-http-requests-with-python-and-asyncio/