tty unblocking setraw and save-restore features

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2020-04-08.17:44:06.826>
labels = ['3.7', 'type-bug', 'library']
title = 'tty unblocking setraw and save-restore features'
updated_at = <Date 2020-04-08.17:47:31.816>
user = 'https://github.com/StevenLu2004'

bugs.python.org fields:

activity = <Date 2020-04-08.17:47:31.816>
actor = 'python-dev'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2020-04-08.17:44:06.826>
creator = 'Steven Lu'
dependencies = []
files = []
hgrepos = []
issue_num = 40229
keywords = ['patch']
message_count = 1.0
messages = ['365996']
nosy_count = 2.0
nosy_names = ['python-dev', 'Steven Lu']
pr_nums = ['19440']
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue40229'
versions = ['Python 3.7']