First of all, thank you very much for contributing to SlmMail. We don't ask you a lot: just make sure you follow Zend Framework 2 code style conventions. If your PR introduce a new feature, we will ask you one or more unit tests to ensure the code will work correctly in the future. Additionally, we may ask you to add a tiny paragraph of documentation, depending on the change!
SlmMail is currently maintained by Jurian Sluiman (@juriansluiman) and Michaël Gallego (@bakura10). Excepting for typo/docblock fixes that can be merged by any of us, any other PR will require approval from both of us. This is to ensure high quality code.
Therefore, don't worry if we take a few days to merge your change!