Postprocess the request acting on the response.

        Arguments:
            response: The response after the request is finalized.
            request_context: The request context, optional as Flask
                omits this argument.

async def process_response(
        self,
        response: Response,
        request_context: Optional[RequestContext]=None,
    ) -> Response:
        """Postprocess the request acting on the response.

        Arguments:
            response: The response after the request is finalized.
            request_context: The request context, optional as Flask
                omits this argument.
        """
        request_ = (request_context or _request_ctx_stack.top).request
        functions = (request_context or _request_ctx_stack.top)._after_request_functions
        blueprint = request_.blueprint
        if blueprint is not None:
            functions = chain(functions, self.after_request_funcs[blueprint])
        functions = chain(functions, self.after_request_funcs[None])

        for function in functions:
            response = await function(response)

        session_ = (request_context or _request_ctx_stack.top).session
        if not self.session_interface.is_null_session(session_):
            await self.save_session(session_, response)
        return response