From cbaa7cfa93893876e4fd8794b6ea39f4d245b6b5 Mon Sep 17 00:00:00 2001
From: Martin Lucina
Note that offset specifies where the first message begins rather than the first +message part. Thus, if there are trailing message parts at the beginning of +the packet the offset ignores them and points to first initial message part +in the packet.
The following diagram illustrates the layout of a single PGM datagram payload: