Zero byte appends

[Rob Mueller]

>> Some applications (e.g. Kolab) store other objects than Mail (e.g.
>> Addressbooks, Calendar, Tasks or Notes) in IMAP folders. They might
>> create empty objects for some reason.
>
> Well that's pretty evil.  The objects should still have a header,
> right?  Or do they just store blobs?

http://www.faqs.org/rfcs/rfc2822.html

So the body is optional (3.5), but in the headers (3.6), there has to be a 
Date and From header

   The only required header fields are the origination date field and
   the originator address field(s).  All other header fields are
   syntactically optional.  More information is contained in the table
   following this definition.

So really a 0 byte message is not a valid message.

Rob