__arrow_c_stream__ method on DataFrame

[kylebarron]

Pandas added support for the Arrow PyCapsule Interface (the __arrow_c_stream__ method) in pandas v2.2. pandas-dev/pandas#56587

This method returns a C PyCapsule, so it's not the types of arguments or return value that matters, it's really just the existence of the method, so that when other libraries expect an object defined as

class ArrowStreamExportable(Protocol):
    def __arrow_c_stream__(
        self,
        requested_schema: object | None = None
    ) -> object:
        ...

then a DataFrame will satisfy the type checker

• Closes #xxxx (Replace xxxx with the Github issue number)
• Tests added: Please use assert_type() to assert the type of any return value

[Dr-Irv]

Thanks @kylebarron

I'm not sure we would have ever picked this up, because it isn't documented in the pandas release notes.