Asynchronously submits the current contents of this to the D-Bus service to be written to disk and broadcast to other clients.
The this must be writable.
When the operation is finished, callback will be called. You can then call write.end to
get the result of the operation.
| this |
a writable Source |
| cancellable |
optional Cancellable object, or |
| callback |
a TaskReadyCallback to call when the request is satisfied |
| user_data |
data to pass to the callback function |