public void updateValue(final K key, final Consumer<ByteBuffer> valueBufferConsumer) {
        lmdbEnvironment.doWithWriteTxn(writeTxn ->
                updateValue(writeTxn, key, valueBufferConsumer));
    }
This will fail if you are already inside a txn.

@see AbstractLmdbDb#updateValue(Txn, Object, Consumer)
stroom-lmdb/src/main/java/stroom/lmdb/AbstractLmdbDb.java