Sets the given response header name and value.

        All header values are converted to strings (`datetime` objects
        are formatted according to the HTTP specification for the
        ``Date`` header).

def set_header(self, name: str, value: _HeaderTypes) -> None:
        """Sets the given response header name and value.

        All header values are converted to strings (`datetime` objects
        are formatted according to the HTTP specification for the
        ``Date`` header).

        """
        self._headers[name] = self._convert_header_value(value)