lambda (source result)  

source

The g:object instance the asynchronous operation was started with.

result

The g:async-result object.

Type definition for a function that will be called back when an asynchronous operation within GIO has been completed. The g:async-ready-callback callbacks from the g:task object are guaranteed to be invoked in a later iteration of the thread-default main context where the g:task object was created. All other users of the g:async-ready-callback function must likewise call it asynchronously in a later iteration of the main context.