A filter used to restrict the search to a subset of the players on Game Center.
- iOS 4.0+
- macOS 10.8+
- tvOS 9.0+
- watchOS 3.0+
player property is ignored if the leaderboard request was initialized using the
init(player method. Otherwise, the
player property determines which players are included in the request for high scores. The default is
GKLeaderboard for more information.