Bug report

Bug description:

typeing.BinaryIO is completely missing thereadinto method. All binary mode return values ofopen support thereadinto method, and the lack of it on theBinaryIO type makes type-hinting difficult when using this method. One could try to useio.RawIOBase | io.BufferedIOBase but this looses the fact that the result ofopen has aname property. This has been brought up inpython/typing#659 andpython/typeshed#2166.

Furthmore, thewrite method inBinaryIO is declared to only be compatible withUnion[bytes, bytearray] when it should be anything that satisfiescollections.abc.Buffer.

I propose that BinaryIO should look something more like:

classBinaryIO(IO[bytes]):"""Typed version of the return of open() in binary mode."""__slots__= ()@abstractmethoddefreadinto(self,b:collections.abc.Buffer)->int:pass@abstractmethoddefwrite(self,s:collections.abc.Buffer)->int:pass@abstractmethoddef__enter__(self)->'BinaryIO':pass

CPython versions tested on:

CPython main branch

Operating systems tested on:

No response