socketserver.shutdown should stop serve_forever() immediately

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2021-07-28.21:32:39.337>
labels = ['library']
title = 'socketserver.shutdown should stop serve_forever()  immediately'
updated_at = <Date 2021-07-29.07:21:46.545>
user = 'https://github.com/encukou'

bugs.python.org fields:

activity = <Date 2021-07-29.07:21:46.545>
actor = 'petr.viktorin'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2021-07-28.21:32:39.337>
creator = 'petr.viktorin'
dependencies = []
files = []
hgrepos = []
issue_num = 44769
keywords = []
message_count = 2.0
messages = ['398427', '398462']
nosy_count = 1.0
nosy_names = ['petr.viktorin']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = None
url = 'https://bugs.python.org/issue44769'
versions = []