gh-115059: Flush the underlying write buffer in io.BufferedRandom.read1()

[serhiy-storchaka]

• Issue: io.TextIOWrapper.read does not flush the underlying write buffer when given a size argument #115059

[miss-islington-app]

Thanks @serhiy-storchaka for the PR 🌮🎉.. I'm working now to backport this PR to: 3.11, 3.12.
🐍🍒⛏🤖

[bedevere-app]

GH-115206 is a backport of this pull request to the 3.11 branch.

[bedevere-app]

GH-115205 is a backport of this pull request to the 3.12 branch.

[bedevere-app]

GH-115205 is a backport of this pull request to the 3.12 branch.

[bedevere-bot]

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot ARM64 macOS 3.11 has failed when building commit 20c6535.

What do you need to do:

1. Don't panic.
2. Check the buildbot page in the devguide if you don't know what the buildbots are or how they work.
3. Go to the page of the buildbot that failed (https://buildbot.python.org/all/#builders/1030/builds/1724) and take a look at the build logs.
4. Check if the failure is related to this commit (20c6535) or if it is a false positive.
5. If the failure is related to this commit, please, reflect that on the issue and make a new Pull Request with a fix.

You can take a look at the buildbot page here:

https://buildbot.python.org/all/#builders/1030/builds/1724

Failed tests:

• test_ssl

Failed subtests:

• test_preauth_data_to_tls_server - test.test_ssl.TestPreHandshakeClose.test_preauth_data_to_tls_server

Summary of the results of the build (if available):

==

Click to see traceback logs

Traceback (most recent call last):
  File "/Users/buildbot/buildarea/3.11.pablogsal-macos-m1.macos-with-brew/build/Lib/test/test_ssl.py", line 5064, in test_preauth_data_to_tls_server
    self.non_linux_skip_if_other_okay_error(wrap_error)
  File "/Users/buildbot/buildarea/3.11.pablogsal-macos-m1.macos-with-brew/build/Lib/test/test_ssl.py", line 5011, in non_linux_skip_if_other_okay_error
    re.search('wrong.version.number', getattr(err, "reason", ""), re.I)):
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/buildbot/buildarea/3.11.pablogsal-macos-m1.macos-with-brew/build/Lib/re/__init__.py", line 176, in search
    return _compile(pattern, flags).search(string)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: expected string or bytes-like object, got 'NoneType'