Scraper: 'NoneType' object has no attribute 'fileno'

Hi,

Sometimes the scraper fails and does not recover till next restart:

2021-03-24 08:43:51 ERROR (MainThread) [homeassistant.components.sensor] scrape: Error on device update!
Traceback (most recent call last):
  File "/srv/homeassistant/lib/python3.8/site-packages/homeassistant/helpers/entity_platform.py", line 360, in _async_add_entity
    await entity.async_device_update(warning=False)
  File "/srv/homeassistant/lib/python3.8/site-packages/homeassistant/helpers/entity.py", line 465, in async_device_update
    await task
  File "/srv/homeassistant/lib/python3.8/site-packages/homeassistant/components/scrape/sensor.py", line 139, in async_update
    await self.rest.async_update()
  File "/srv/homeassistant/lib/python3.8/site-packages/homeassistant/components/rest/data.py", line 55, in async_update
    response = await self._async_client.request(
  File "/srv/homeassistant/lib/python3.8/site-packages/httpx/_client.py", line 1371, in request
    response = await self.send(
  File "/srv/homeassistant/lib/python3.8/site-packages/httpx/_client.py", line 1406, in send
    response = await self._send_handling_auth(
  File "/srv/homeassistant/lib/python3.8/site-packages/httpx/_client.py", line 1444, in _send_handling_auth
    response = await self._send_handling_redirects(
  File "/srv/homeassistant/lib/python3.8/site-packages/httpx/_client.py", line 1476, in _send_handling_redirects
    response = await self._send_single_request(request, timeout)
  File "/srv/homeassistant/lib/python3.8/site-packages/httpx/_client.py", line 1502, in _send_single_request
    (status_code, headers, stream, ext,) = await transport.arequest(
  File "/srv/homeassistant/lib/python3.8/site-packages/httpcore/_async/connection_pool.py", line 208, in arequest
    connection = await self._get_connection_from_pool(origin)
  File "/srv/homeassistant/lib/python3.8/site-packages/httpcore/_async/connection_pool.py", line 248, in _get_connection_from_pool
    if connection.is_socket_readable():
  File "/srv/homeassistant/lib/python3.8/site-packages/httpcore/_async/connection.py", line 168, in is_socket_readable
    return self.connection is not None and self.connection.is_socket_readable()
  File "/srv/homeassistant/lib/python3.8/site-packages/httpcore/_async/http11.py", line 205, in is_socket_readable
    return self.socket.is_readable()
  File "/srv/homeassistant/lib/python3.8/site-packages/httpcore/_backends/asyncio.py", line 182, in is_readable
    return is_socket_readable(sock.fileno())
AttributeError: 'NoneType' object has no attribute 'fileno'

Reported on HA 2021.3.2