Increment an achievement.
Achievement takes two parameters:
androidID the achievement ID for Google Play Games.
steps If the achievement is of the incremental type
you can use this method to increment the steps.
Save game with data and a unique name.
The name must be between 1 and 100 non-URL-reserved characters (a-z, A-Z, 0-9, or the symbols "-", ".", "_", or "~").
Open the device's default leaderboards screen. If a leaderboard ID is provided,
it will display the specific leaderboard, otherwise it will show the list of all leaderboards.
Sign the user into Game Center or Google Play Games. This must be called before
taking any action (such as submitting a score or unlocking an achievement).
Submit a score to a specific leaderboard.
Score takes three parameters:
androidLeaderboardID the leaderboard ID for Google Play Games.
iOSLeaderboardID the leaderboard ID for Game Center.
value the score.
Unlock an achievement.
Achievement takes three parameters:
androidID the achievement ID for Google Play Games.
iOSID the achievement ID for Game Center.
percentComplete the completion percentage of the achievement,
this parameter is optional on iOS/macOS.