Creates a source that triggers if cancellable is cancelled and
calls its callback of type #GCancellableSourceFunc. This is
primarily useful for attaching to another (non-cancellable) source
with glib.source.Source.addChildSource to add cancellability to it.
For convenience, you can call this with a null #GCancellable,
in which case the source will never trigger.
The new #GSource will hold a reference to the #GCancellable.
Creates a source that triggers if cancellable is cancelled and calls its callback of type #GCancellableSourceFunc. This is primarily useful for attaching to another (non-cancellable) source with glib.source.Source.addChildSource to add cancellability to it.
For convenience, you can call this with a null #GCancellable, in which case the source will never trigger.
The new #GSource will hold a reference to the #GCancellable.