get_data
Description:
Asynchronously get the raw data for this.
When the operation is finished, callback will be called. You can then call get_data.end to get the
result of the operation.
Parameters:
| this | |
| cancellable |
a Cancellable or null to ignore |
| callback |
a TaskReadyCallback to call when the request is satisfied |
| user_data |
the data to pass to callback function |