Content Delivered : when Gimbal delivers content to the Gimbal SDK/App. The event may or may not be shown to the user notification tray.
Content Notified : when the Gimbal SDK/App shows notification to the user in iOS/Android notification tray.
Content Pushed: Only applicable for Instant Push/ Time-triggered. These events uses Google/Apple PUSH server to push these events to the Android/iOS end-user notification tray
Content Clicked: The notification was clicked from the notification tray