completed

Whether the task has completed, meaning its callback (if set) has been invoked. This can only happen after g_task_return_pointer(), g_task_return_error() or one of the other return functions have been called on the task.

This property is guaranteed to change from false to true exactly once.

The #GObject::notify signal for this change is emitted in the same main context as the task’s callback, immediately after that callback is invoked.