Asynchronously subscribes to the folder described by folder_name.
When the operation is finished, callback will be called. You can then call subscribe_folder.end
to get the result of the operation.
| this | |
| folder_name |
full path of the folder |
| io_priority |
the I/O priority of the request |
| cancellable |
optional Cancellable object, or null |
| callback |
a TaskReadyCallback to call when the request is satisfied |
| user_data |
data to pass to the callback function |