Updates task to online tasks service.
this and task are both reffed when this function is called, so can safely be unreffed
after this function returns.
callback should call update_entry_async.end to obtain a
TasksTask representing the updated task and to check for possible errors.
For more details, see update_task, which is the synchronous version of this function, and update_entry_async, which is the base asynchronous insertion function.
| this | |
| task |
TasksTask to update |
| cancellable |
optional Cancellable object, or |
| callback |
a TaskReadyCallback to call when insertion is finished |
| user_data |
data to pass to the |