preview property
Preview is the first 240 bytes of the event's payload, cut without regard for the JSON inside it — it is a string to SHOW, never a value to parse. Read the detail or the stream for the whole payload.
Please note: This property should have been non-nullable! Since the specification file does not include a default value (using the "default:" property), however, the generated source code must fall back to having a nullable type. Consider adding a "default:" property in the specification file to hide this note.
Implementation
String? preview;