@Override
    public void checkpointStarted(CheckpointBarrier barrier) throws CheckpointException {
        throw new CheckpointException(CHECKPOINT_DECLINED_TASK_NOT_READY);
    }
@Test
    void testCheckpointStartImpossible() {
        assertThatThrownBy(
                        () ->
                                buildChannel()
                                        .checkpointStarted(
                                                new CheckpointBarrier(
                                                        0L,
                                                        0L,
                                                        unaligned(
                                                                CheckpointType.CHECKPOINT,
                                                                getDefault()))))
                .isInstanceOf(CheckpointException.class);
    }