[BUG] Unable to make simultaneous asynchronous requests

[ZentixUA]

Describe the bug
Making multiple simultaneous requests to a single host results in a curl error if a TCP connection to the requested host was established earlier (a request was made previously).

To Reproduce

1. Install httpx using pip install httpx
2. Install curl-cffi using pip install curl-cffi
3. Run this code:

import asyncio
import sys

from curl_cffi.requests import AsyncSession
from httpx import AsyncClient

BASE_URL = 'https://images.pexels.com'
PATHS = ['/photos/842711/pexels-photo-842711.jpeg'] * 2


async def test_httpx():
    print('----- httpx -----')
    async with AsyncClient() as session:
        await session.get(BASE_URL)
        tasks = [session.get(BASE_URL + path) for path in PATHS]
        print(await asyncio.gather(*tasks))


async def test_curl_cffi():
    print('----- curl-cffi -----')
    async with AsyncSession() as session:
        await session.get(BASE_URL)
        tasks = [session.get(BASE_URL + path) for path in PATHS]
        print(await asyncio.gather(*tasks))


if __name__ == '__main__':
    if sys.platform == 'win32':
        asyncio.set_event_loop_policy(asyncio.WindowsSelectorEventLoopPolicy())
    asyncio.run(test_httpx())
    asyncio.run(test_curl_cffi())

Expected behavior
The requests will be successfully completed and the bytes of the requested images will be received with an HTTP status of 200, as occurs when using httpx.

Versions

• OS: Windows 11
• curl_cffi version: 0.6.2
• pip freeze dump:

anyio==4.3.0
certifi==2024.2.2
cffi==1.16.0
curl_cffi==0.6.2
exceptiongroup==1.2.0
h11==0.14.0
httpcore==1.0.5
httpx==0.27.0
idna==3.7
pycparser==2.22
sniffio==1.3.1
typing_extensions==4.11.0

Additional context

• Which session are you using? Async.
• If using async session, which loop implementation are you using? Asyncio.

[yifeikong]

A temporary fix is to force http/1.1, I'm still investigating a further solution.

- async with AsyncSession() as session:
+ async with AsyncSession(http_version=CurlHttpVersion.V1_1) as session:

[ZentixUA]

Hello! Are there any new details on the issue?

[ZentixUA]

Hello again, any updates?