Update `bytearray` to contain a `bytes` and provide a zero-copy path to "extract" the `bytes`. This allows making several code paths more efficient. This does not move any codepaths to make use of this new API. The documentation changes include common code patterns which can be made more efficient with this API. --- When just changing `bytearray` to contain `bytes` I ran pyperformance on a `--with-lto --enable-optimizations --with-static-libpython` build and don't see any major speedups or slowdowns with this; all seems to be in the noise of my machine (Generally changes under 5% or benchmarks that don't touch bytes/bytearray). Co-authored-by: Victor Stinner <vstinner@python.org> Co-authored-by: Maurycy Pawłowski-Wieroński <5383+maurycy@users.noreply.github.com>
The Python C API ================ The C API is divided into these sections: 1. ``Include/``: Limited API 2. ``Include/cpython/``: CPython implementation details 3. ``Include/cpython/``, names with the ``PyUnstable_`` prefix: API that can change between minor releases 4. ``Include/internal/``, and any name with ``_`` prefix: The internal API Information on changing the C API is available `in the developer guide`_ .. _in the developer guide: https://devguide.python.org/c-api/