Message-Id Header

[branzo]

Please update documentation, and eventually the code to take into account the automatic addition of a proper Message-Id as it may
happen that the first-hop SMTP server used to the send the email is not actively adding the missing header.

[carlosbet]

With this automatically adding a valid message ID header, and also you can set your custom headers such as System.Net.Mail does. For example:

MimeMailMessage msg = new();
msg.HeadersEncoding = Encoding.UTF8;
msg.Headers.Add("X-HeaderName", "HeaderValue");
...

Umm, and this makes me reconsider that maybe it's not a good idea to use the HeadersEncoding property to determine encoding in address fields and should be isolated in MimeMailAddress such I did make initially. At this point, I mean this: #30