@Override
    public void close() throws IOException {
        // users should not be able to actually close the stream, it is closed by the system.
        // TODO if we want to support async writes, this call could trigger a callback to the
        // snapshot context that a handle is available.
    }
@Test
    void testCloseNotPropagated() throws Exception {
        KeyedStateCheckpointOutputStream stream = createStream(new KeyGroupRange(0, 0));
        TestMemoryCheckpointOutputStream innerStream =
                (TestMemoryCheckpointOutputStream) stream.getDelegate();
        stream.close();
        assertThat(innerStream.isClosed()).isFalse();
    }