Asynchronously gets a reference to the authority.
This is an asynchronous failable function. When the result is ready, callback will be invoked in the <link
linkend="g-main-context-push-thread-default">thread-default main loop</link> of the thread you are calling this method from and
you can use get_async.end to get the result. See
get_sync for the synchronous version.
| cancellable |
A Cancellable or null. |
| callback |
A TaskReadyCallback to call when the request is satisfied. |
| user_data |
The data to pass to |