header field) when saving a message using the MsgBase class.
A similar problem existed with REPLYTOLIST/RFC822REPLYTO, but was not actually
observed.
Since the following header fields were not populated in the msg header
"field_list", if they existed in a message header that was modified using
the MsgBase class, they would be lost:
- RFC822TO
- RFC822CC
- RFC822ORG
- RFC822REPLYTO
- RFC822SUBJECT