[TSharedPtr](API\Runtime\Core\Templates\TSharedPtr)< const [IGroupRoster](API\Plugins\OnlineSubsystem\Interfaces\IGroupRoster) > GetCachedGroupRoster ( const [FUniqueNetId](API\Runtime\CoreOnline\Online\FUniqueNetId) & ContextUserId, const [FUniqueNetId](API\Runtime\CoreOnline\Online\FUniqueNetId) & GroupId )