- Code re-organization: exposing multi-execution of non-queries as two separate methods: MultiExecuteAsync and MultiExecuteAsyncSerialized, the latter awaits each sql command before calling the next, serializing their execution at the client level, while the former allows pipelining the commands at the server, requiring the driver to have specific support (MARS).

- Modified ExecuteAsync with additional "serialized" argument, to pick which of the above to call.