Stop recording.

async def stop(self):
        """
        Stop recording.
        """
        if self.__container:
            for track, context in self.__tracks.items():
                if context.task is not None:
                    context.task.cancel()
                    context.task = None
                    for packet in context.stream.encode(None):
                        self.__container.mux(packet)
            self.__tracks = {}

            if self.__container:
                self.__container.close()
                self.__container = None