X-mmm-1: class, name, parent, list of property/value pairs
X-mmm-2: class, name, parent, list of property/value pairs
X-mmm-3: class, name, parent, list of property/value pairs
X-mmm-total: 3 (total number of "X-mmm-[number]:" keys)
X-mmm-body: class, name, parent, list of property/value pairs (text is the msg
             body, found after all the headers).