Thread Specific Storage (TSS) API is a public C API (new in 3.7).

* bpo-33263 Fix FD leak in _SelectorSocketTransport. (GH-6450)

Under particular circumstances _SelectorSocketTransport can try to add a reader
even the transport is already being closed. This can lead to FD leak and
invalid stated of the following connections. Fixed the SelectorSocketTransport
to add the reader only if the trasport is still active.

Look for '__set__' or '__delete__'.

Also remove bullet asterisks from IDLE entries.

Fix typo from commit 6370f345Signed-off-by: Christian Heimes <christian@python.org>

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<!-- issue-number: bpo-32262 -->
https://bugs.python.org/issue32262
<!-- /issue-number -->

Function was added with the initial implementation 00efe7e7.

uuid._ipconfig_getnode did not validate the maximum length of the value,
so long as the value had the same type of formatting as a MAC address.
This let it select DUIDs as MAC addresses. It now requires an exact
length match.

CPython 3.5 is old now, and we don't bump this version often,
so lets avoid using specific versions.

Fix the following bugs in the C implementation:

* get_future_loop() silenced all exceptions raised when look up the get_loop
  attribute, not just an AttributeError.
* enter_task() silenced all exceptions raised when look up the current task,
  not just a KeyError.
* repr() was called for a borrowed link in enter_task() and task_step_impl().
* str() was used instead of repr() in formatting one error message (in
  Python implementation too).
* There where few reference leaks in error cases.

The proactor event loop has a race condition when reading with
pausing/resuming. `resume_reading()` unconditionally schedules the read
function to read from the current future. If `resume_reading()` was
called before the previously scheduled done callback fires, this results
in two attempts to get the data from the most recent read and an
assertion failure. This commit tracks whether or not `resume_reading`
needs to reschedule the callback to restart the loop, preventing a
second attempt to read the data.

A DeprecationWarning was emitted in Python 3.6-3.7.

This will make it easier to clean up channels (e.g. when used in tests).

Patch by Thomas Jones.

`obj.async` is now a syntax error, so the warning/shim is
quasi-unnecessary.