public Optional<V> get(final K key) {
        return lmdbEnvironment.getWithReadTxn(txn ->
                get(txn, key));
    }
Gets the de-serialised value (if found) for the passed key using a read txn.
This will fail if you are already inside a txn.
stroom-lmdb/src/main/java/stroom/lmdb/AbstractLmdbDb.java