Client sessions are not closed on client close

[mbrancato]

The aiohttp.ClientSession is not closed properly after close() is called on a client.

e.g.

import aiohttp
import logging

from gcloud.aio.pubsub import PublisherClient

logging.basicConfig(level=logging.DEBUG)
logger = logging.getLogger("test")

async def foo():
    pubsub_conn = aiohttp.TCPConnector(limit=50)
    pubsub_session = aiohttp.ClientSession(connector=pubsub_conn)
    pubsub_client = PublisherClient(session=pubsub_session)
    logger.info("done")
    await pubsub_client.close()


asyncio.run(foo())

DEBUG:asyncio:Using selector: KqueueSelector
INFO:test:done
ERROR:asyncio:Unclosed client session
client_session: <aiohttp.client.ClientSession object at 0x107ea8460>

The only way I've been able to avoid these is to explicitly call await pubsub_session.close() or by calling await pubsub_client.session.session.close().