get
Gets the custom properties associated with this event, providing additional contextual information.
Properties are represented as a map of key-value pairs. Keys are strings, and values can be various simple data types (e.g., String, Number, Boolean). These properties allow for richer, more detailed event data. For example, a "CONTENT_PLAYED" event might have properties like "content_id: 123", "duration_ms: 30000", "played_by_user: true".
The returned map might be unmodifiable if the event instance is immutable.
Return
A non-null, potentially unmodifiable map of event properties. Returns an empty map if no properties are associated with this event.