@AfterAll
    static void afterAll() {
        executor.shutdown();
        BYTE_BUFFER_POOL.clear();
    }
Demonstrate the behaviour of too many readers trying to do a get() on LMDB at once
where concurrent readers > maxReaders setting. Tests the concurrency protection in
{@link LmdbEnv}
stroom-lmdb/src/test/java/stroom/lmdb/TestLmdbEnv.java