[update based on review of message/partial]
Bruce Lilly wrote:
Body contains header of original message, including the Message-ID: X
and any References fields (N.B. these are in the *body* of message 1).
The References field (if present) from the original (unfragmented)
message would appear in the header rather than body, however the
Message-ID of the original is in the body of message 1.
Body contains fields of fragment 3, which has been further split,
including (in the *body*) Message-ID: 3 and References: 2.
As above. The header here contains
A UA which is intended to thread messages by following References and
In-Reply-To header fields will have to do several things:
1. It needs to determine whether a given References field is part of a
reply thread or part of a series of partial message fragments. If
the message has a Content-Type field specifying a media type of
message/partial, it is the latter.
2. It needs to (at least virtually) reassemble fragmented messages in
order to find the message header (which is encapsulated in the first
part of the message/partial fragment series), which in turn is necessary
in order to follow Message-ID, In-Reply-To, and References fields. It's
also necessary in order to display the correct information for the
original message (as opposed to uninteresting information on a series
In-Reply-To and References would appear in the header of the first piece.
Message-ID still requires reassembly (or examination of the first piece body).