Register for transport ready events.  The `transport ready`
        event is raised via a user callback.  If the endpoint
        is configured as a source, then the user may then
        call :py:meth:`write_transport` in order to send data to
        the associated sink.
        Otherwise, if the endpoint is configured as a sink, then
        the user may call :py:meth:`read_transport` to read
        from the associated source instead.

        :param func user_cb: User defined callback function.  It
            must take one parameter which is the user's callback
            argument.
        :param user_arg: User defined callback argument.
        :return:

        See also: :py:meth:`unregister_transport_ready_event`

def register_transport_ready_event(self, user_cb, user_arg):
        """
        Register for transport ready events.  The `transport ready`
        event is raised via a user callback.  If the endpoint
        is configured as a source, then the user may then
        call :py:meth:`write_transport` in order to send data to
        the associated sink.
        Otherwise, if the endpoint is configured as a sink, then
        the user may call :py:meth:`read_transport` to read
        from the associated source instead.

        :param func user_cb: User defined callback function.  It
            must take one parameter which is the user's callback
            argument.
        :param user_arg: User defined callback argument.
        :return:

        See also: :py:meth:`unregister_transport_ready_event`
        """
        self.user_cb = user_cb
        self.user_arg = user_arg