Memory leak in async client

[Bechma]

Maybe it's related to a similar issue in requests psf/requests#4601
This situation with aiohttp does not happens, here is a sample code to test it out.

import asyncio

import httpx


async def request(client):
    """Should make a petition and free the response afterwards"""
    response = await client.get("http://httpbin.org/bytes/3000000")
    first_10_bytes = response.content[:10]
    last_10_bytes = response.content[:-10]
    await response.aclose()


def get_current_memory_usage():
    """Memory usage in kB"""
    with open('/proc/self/status') as f:
        memusage = f.read().split('VmRSS:')[1].split('\n')[0][:-3]
    return int(memusage.strip())


async def main():
    """Main module"""
    while True:
        print("Memory usage:", get_current_memory_usage(), "kB")
        async with httpx.AsyncClient() as client:
            await asyncio.gather(*[request(client) for _ in range(10)])
        await asyncio.sleep(1)


if __name__ == '__main__':
    asyncio.run(main())

Output:

Memory usage: 23036 kB
Memory usage: 33008 kB
Memory usage: 34328 kB
Memory usage: 35180 kB
Memory usage: 35316 kB
Memory usage: 35844 kB
Memory usage: 35844 kB
Memory usage: 35844 kB
Memory usage: 35844 kB
Memory usage: 36348 kB
Memory usage: 37140 kB
Memory usage: 38196 kB
Memory usage: 38196 kB
Memory usage: 38196 kB
Memory usage: 38196 kB
Memory usage: 38196 kB
Memory usage: 38196 kB
Memory usage: 38460 kB
Memory usage: 38460 kB
Memory usage: 38460 kB
Memory usage: 38460 kB
Memory usage: 38460 kB
Memory usage: 38460 kB
Memory usage: 38724 kB
Memory usage: 38724 kB
Memory usage: 38724 kB
Memory usage: 38724 kB
Memory usage: 38724 kB
Memory usage: 38724 kB
Memory usage: 38724 kB
Memory usage: 38724 kB
Memory usage: 38724 kB
Memory usage: 38724 kB
Memory usage: 38724 kB

Stack:
Python 3.9
httpx 0.20 (0.19 has also the same problem)
WSL2 (docker, python:3.9) (Tested in Windows with similar leak results)

[lovelydinosaur]

I....... would not classify that as a memory leak.
I mean, I wouldn't neccessarily not, but it's taken some memory, and then remained stable, so?

Absolutely up for any useful or actionable insights as to exactly where memory is most used within httpx. I'd expect the SSLContext is a good place to dig into.