`tarfile.open()` does not forward keyword arguments to the underlying `_Stream` object for zstd in stream mode

Bug report

Bug description:

I found the bug when I was browsing the source code, so I just put the source code here:

    @classmethod
    def open(cls, name=None, mode="r", fileobj=None, bufsize=RECORDSIZE, **kwargs):
        # irrevalent code...
        elif "|" in mode:
            # irrevalent code...
            compresslevel = kwargs.pop("compresslevel", 6)
            preset = kwargs.pop("preset", None)
            stream = _Stream(name, filemode, comptype, fileobj, bufsize,
                             compresslevel, preset)
            # irrevalent code...

But the doc says that:

For modes 'w:zst', 'x:zst' and 'w|zst', tarfile.open() accepts the keyword argument level to specify the compression level of the file. The keyword argument options may also be passed, providing advanced Zstandard compression parameters described by CompressionParameter. The keyword argument zstd_dict can be passed to provide a ZstdDict, a Zstandard dictionary used to improve compression of smaller amounts of data.

So there're three keyword arguments: level, options and zstd_dict that need to pass to _Stream constructor, and the constructor needs to change to accept these keyword arguments.

I'll open a PR to fix this soon.

CPython versions tested on:

3.14

Operating systems tested on:

No response

Linked PRs

• gh-139822

Parti da tarfile.open() e dal costruttore _Stream, concentrandoti sulle modalità di stream che utilizzano zstd. Verifica come debbano essere inoltrati level, options e zstd_dict e conferma che il comportamento corrispondente della documentazione funzioni per w|zst; la PR collegata indica che questo lavoro è già in corso.