aiosmtplib: SMTP.quit produces warning "Future exception was never retrieved"

I ported this code from my old implementation on standard smtplib module, and perhaps it is not correct for aiosmtplib. But i think this shouldn’t matter.

import asyncio
import aiosmtplib
from email.mime.text import MIMEText
from email.header import Header
async def send_mail(host, login, password, from_addr, to_addr, subject, body_text):
	msg=MIMEText(*body_text)
	msg['Subject']=Header(subject, 'utf-8')
	msg['From']=from_addr
	msg['To']=to_addr
	server=aiosmtplib.SMTP(host)
	await server.connect()
	await server.starttls()
	await server.login(login, password)
	try:
		await server.sendmail(from_addr, [to_addr], msg.as_string())
	except (aiosmtplib.SMTPRecipientsRefused, aiosmtplib.SMTPSenderRefused):
		return 1
	finally:
		await server.quit()
#code for testing
async def start():
	await send_mail('smtp.yandex.ru', 'a@b.c', '1234', 'a@b.c', 'x@y.z', 'Testing', ['Hello', 'plain', 'utf-8'])
	print('success')
#emulating work of other asyncio tasks...
	await asyncio.sleep(3)
asyncio.run(start())```

```Python 3.7.2 (tags/v3.7.2:9a3ffc0492, Dec 23 2018, 23:09:28) [MSC v.1916 64 bit (AMD64)] on win32
>>> import mail_test
success
>>> exit()
Future exception was never retrieved
future: <Future finished exception=SMTPServerDisconnected('Unexpected EOF received')>
aiosmtplib.errors.SMTPServerDisconnected: Unexpected EOF received```

If i comment two last lines of my function, it works good.

```>>> import mail_test
success
>>> exit()```