+ *
+ * IMPORTANT NOTES:
+ * 1) if you want to reuse the message, as a recommendation, you should set engine to
+ * NULL or use #clear. In that way, next operation will adjust automatically the needed
+ * engine because it would not be configured in such stage.
+ * 2) if you want to pre-configure the engine you will need to set the engine to NULL
+ * previously and then you could change to the new one without warning/ignoring.
+ * 3) if you have dedicated message objects for each interface (application id), then
+ * you could set the corresponding engine on constructor (or setEngine), and forget
+ * about #clear. The needed cleanup will be done automatically from decoding and xml
+ * loading procedures, and initialized engine will be kept along message operations.