The result of Unicom360.WhatsApp.send_session/3 (canonical name SessionSendResult).
api_reference,message- from the envelope.message_id- the message's id (a string); pass it toUnicom360.WhatsApp.status/3, or as a later message's:reply_to.to,user_reference_id,status("ACKNOWLEDGED"),category("SERVICE").raw,extra- the JSON object, and the members this version does not model.