EventExecutor::close-method throws NPE

[JohannesLichtenberger]

    void close() {
        ring.close();
        bufRings.values().forEach(IoUringBufRing::close);
    }

the bufRings instance should in either way be initialized to an empty map instead of null if the condition returns false.

[ikorennoy]

Oops, I thought I had fixed it, thank you.

Please update to 0.0.6 and the problem should be gone.