String Binary File is just expecting BytesIO and not filename and mime-type

I have Java OpenAPI server which provides an upload endpoint (POST) that expect as schema a FileRequest ( schema = @Schema(implementation = FileRequest.class))

The FileRequest looks like:

@Value.Immutable
@JsonDeserialize(builder = com.mydata.request.FileRequest.Builder.class)
public abstract class FileRequest implements FileFields {
    @Schema(type = "string", format = "binary", description = "File")
    @JsonProperty
    public abstract String file();

    public static class Builder extends ImmutableFileRequest.Builder {

    }
}

Looking at the generated code, the models looks good. This is the relevant part on types.py:

@attr.s(auto_attribs=True)
class File:
    """ Contains information for file uploads """

    payload: BinaryIO
    file_name: Optional[str] = None
    mime_type: Optional[str] = None

    def to_tuple(self) -> FileJsonType:
        """ Return a tuple representation that httpx will accept for multipart/form-data """
        return self.file_name, self.payload, self.mime_type


T = TypeVar("T")

However, looking at the upload endpoint request, it doesn't expect the Optional values above:

    @classmethod
    def from_dict(cls: Type[T], src_dict: Dict[str, Any]) -> T:
        d = src_dict.copy()

        _file = d.pop("file", UNSET)
        file: Union[Unset, File]
        if isinstance(_file,  Unset):
            file = UNSET
        else:
            file = File(
             payload = BytesIO(_file)
        )

Notice that the File expects only the binary data, losing the filename and mimetype.

Expected behavior

I would expect that the generated code would look something like below, which I patched and am using currently:

        else:
            file = File(
             payload = BytesIO(_file['payload']),
                file_name=_file['filename']
        )

Desktop (please complete the following information):

• OS: Linux, but irrelevant
• openapi-python-client version: 0.11.1
• Python 3.8.10
• openapi: 3.0.1

Start with the generated types.py and the File.from_dict code shown in the issue, then trace how binary string schemas are represented during response or request parsing. Reproduce the supplied FileRequest upload case and verify that the resulting File preserves payload, filename, and MIME type rather than only the binary data.