Hmm, now I'm really confused. If you're about to transmit a set of
messages, and what you have is an mbox file whose format you think you
understand, why don't you package it up as a proper MIME multipart
before transmitting??? -- Nathaniel
because for many things, in practice, mbox files work better than
MIME multiparts. more tools read and write mbox files than read
and write MIME multiparts. MUAs tend to handle messages within
MIME multiparts poorly - for instance, they often don't let you
reply to them, refile them to other folders, etc. MIME multipart
doesn't have the property that you can add messages to it by
appending to the file.