Avoid releasing the GIL in nonblocking socket operations

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2021-11-16.18:51:40.323>
labels = ['3.11', 'expert-asyncio', 'expert-IO', 'performance']
title = 'Avoid releasing the GIL in nonblocking socket operations'
updated_at = <Date 2022-02-02.23:18:52.305>
user = 'https://github.com/jcrist'

bugs.python.org fields:

activity = <Date 2022-02-02.23:18:52.305>
actor = 'jakirkham'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['IO', 'asyncio']
creation = <Date 2021-11-16.18:51:40.323>
creator = 'jcristharif'
dependencies = []
files = ['50443']
hgrepos = []
issue_num = 45819
keywords = ['patch']
message_count = 3.0
messages = ['406422', '406431', '406436']
nosy_count = 6.0
nosy_names = ['rhettinger', 'christian.heimes', 'asvetlov', 'yselivanov', 'jakirkham', 'jcristharif']
pr_nums = ['29579']
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = 'performance'
url = 'https://bugs.python.org/issue45819'
versions = ['Python 3.11']