allowedMetadataKeys property
ENH-96: default-DENY allowlist for winWithMetadata/loseWithMetadata — see GameSessionController.withTimeline's doc. Empty by default (the 2 pre-ENH-96 constructors), meaning win/lose (which pass no metadata anyway) and any metadata a caller passes are both recorded with an empty sanitized map.
Implementation
final Set<String> allowedMetadataKeys;