Open
Description
It looks like it is currently not possible to set the priority / importance of an outgoing email. This could be useful to e.g further highlight emails generated by certain log entry categories. I couldn't find dedicated support for this header in the used ruby gem, so this would need to be implemented using a custom header (``X-Priority`). It might be reasonable to leave this up to the user (especially as this header is only partially standardized) and just allow passing any kind of headers to the gem.