Retrieve stats from the designated cloud storage of the current player.
The data is requested in an async call, so the result isn't available immediately.
When the call completes the
getstats event will be emitted along with the data object returned.
If the call fails, i.e. it's not in the list of supported APIs, or the request was rejected,
it will emit a
getstatsfail event instead.
An optional array of unique keys to retrieve stats for. If the function is called without it, it will fetch all stats.
This Facebook Instant Games Plugin instance.