Feature or enhancement

Proposal:

There's new PyBytesWriter() API:

• https://peps.python.org/pep-0782/

There's an ongoing effort of introducing it in various places:

• https://github.com/python/cpython/pulls?q=is%3Apr+pybyteswriter+is%3Aclosed

With its PyList_Append

and PyBytes_Join:

https://github.com/python/cpython/blob/2ca3c85054b231505c5e6f5f3209eb5f63942dce/Modules/_io/iobase.c#L1010C14-L1010C26

the io.RawIOBase.readall looks like the ideal candidate for PyBytesWriter.

Notably, io.RawIOBase is used internally across many modules:

https://github.com/search?q=repo%3Apython%2Fcpython+io.RawIOBase+path%3A%2F%5ELib%5C%2F%2F&type=code

and some even call readall explicitly sometimes:

Has this already been discussed elsewhere?

No response given

Links to previous discussion of this feature:

No response

Linked PRs

• gh-140135: use PyBytesWriter in io.RawIOBase.readall; 3.98x faster #140139