Type Buffer's flags argument

[jakirkham]

Ensure the flags argument in Buffer is correctly typed so it can be passed verbatim to PyObject_GetBuffer. This can also avoid needless conversions to and from Python object type.

TODO:

• Unit tests and/or doctests in docstrings
• Tests pass locally
• Docstrings and API docs for any new/modified user-facing classes and functions
• Changes documented in docs/release.rst
• Docs build locally
• GitHub Actions CI passes
• Test coverage to 100% (Codecov passes)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.88%. Comparing base (145f57c) to head (c1c95fe).
Report is 4 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #648   +/-   ##
=======================================
  Coverage   99.88%   99.88%           
=======================================
  Files          62       62           
  Lines        2723     2723           
=======================================
  Hits         2720     2720           
  Misses          3        3           

---- 🚨 Try these New Features:

• Flaky Tests Detection - Detect and resolve failed and flaky tests

[jakirkham]

The flags argument here is only used in this PyObject_GetBuffer call. The signature of this function in Cython or in Python is

int PyObject_GetBuffer(object obj, Py_buffer *view, int flags)

Here flags is an int specified by a range of possible constants to provide a specific kind of Py_buffer object

To make sure that flags can be passed through unaltered to this function call, this types the __cinit__ arguments to match

Without this typing, Cython will convert values to Python objects first and then convert them back in this constructor (a needless exercise). This change will fix that issue going forward

[jakirkham]

Thanks David! 🙏