The tracking ID for the event. The ID is generated by a call to the <a href="https://docs.aws.amazon.com/personalize/latest/dg/API_CreateEventTracker.html">CreateEventTracker</a> API.

The user associated with the event.

The session ID associated with the user's visit. Your application generates the sessionId when a user first visits your website or uses your application. Amazon Personalize uses the sessionId to associate events with the user before they log in. For more information, see <a href="https://docs.aws.amazon.com/personalize/latest/dg/recording-events.html">Recording Events</a>.