PyTuple_New(0) always returns the same empty tuple from its free list anyway,
so we are not saving much here. Plus, the code where this was used is on
uncommon run paths.

I have noticed a race-condition occurring on one of the buildbots because of
this optimization. The function called may release the GIL which means
multiple threads may end up accessing the shared tuple. I could fix it up by
storing the tuple to the Pickler and Unipickler object again, but honestly it
really not worth the trouble.

I ran many benchmarks and the only time the optimization helps is when using a
fin-memory file, like io.BytesIO on which reads are super cheap, combined with
pickle protocol less than 4. Even in this contrived case, the speedup is a
about 5%. For everything else, this optimization does not provide any
noticable improvements.

Based on patches by Christian Heimes and Vajrasky Kok

Based on patches by Christian Heimes and Vajrasky Kok

This implements PEP 3121 module finalization as well. This change does not
cause any significant impact on performance.

asyncio: Change write buffer use to avoid O(N**2). Make write()/sendto() accept bytearray/memoryview too. Change some asserts with proper exceptions.

The limit is now 178,956,969 on 64 bit (it is greater on 32 bit because
structures are smaller).

Use int instead of Py_ssize_t to store the number of frames to have smaller
traceback_t objects.

documentation. Use also the term "current" for the current size.

Patch by Claudiu Popa.

I fixed the bug that was in my previous attempt of this cleanup. I ran
the full test suite to verify I didn't introduce any obvious bugs.

This test requires the ifconfig executable on $PATH, /sbin/, or /usr/sbin.

This test requires the ifconfig executable on $PATH, /sbin/, or /usr/sbin.

pythoncore sub-project.  This should prevent build errors due a previous
build's python(_d).exe still running.

pythoncore sub-project.  This should prevent build errors due a previous
build's python(_d).exe still running.

of the time.  Patch by Julian Gindi.

virtual interface.  Original patch by Kent Frazier.

virtual interface.  Original patch by Kent Frazier.