See a working demo of Jingle session management
I'm working on updates to XEP-0166 to add implementation guidance, but I'm going to share the CliffsNotes version here in the meantime since people are looking at creating new implementations.
I have worked on multiple Jingle implementations (and multiple iterations of each) for five years now, on various platforms and languages (Python, Lua, JavaScript, Swift). However, it has only been this past year that I've "achieved enlightenment" and finally understood what the processing model