sessionEvent

Session events occur when a user opens or returns to the app after some inactivity.

Field	Type	Description
length_milliseconds	int	The length of the session in milliseconds
start	timestamp	The date and time in UTC at which the event happened. This timestamp doesn't include the timezone.
install_id	string	justtrack's identifier for the install event tied to this event
attribution_id	string	justtrack's identifier for the attribution event tied to this event