Returns a tuple of the current size of the pending batch queue
        and the current queue limit.

def pending_batch_info(self):
        """Returns a tuple of the current size of the pending batch queue
        and the current queue limit.
        """
        c_length = ctypes.c_int(0)
        c_limit = ctypes.c_int(0)
        self._call(
            'pending_batch_info',
            ctypes.byref(c_length),
            ctypes.byref(c_limit))

        return (c_length.value, c_limit.value)