CoreMailer.sendMail() needs to accept:

1. attachments of various types (byte[] and File)

2. mime types

For example, I should be able to attach an AQProjectFile (will get byte[]), specifying a mime type; at the same time atttach a file, also specifying a mime type. 

I guess with the existing design where a single sendMail() method requires 8 arguments it is difficult to do that without passing some kind of mime-type,attachment pair array.  it would have been easier if CoreMailer class accepted AQMailMessage object instead, which can be interrogated and all the necessary parts retrieved.

See CoreSmtpServer.send().