Implementors of cancellable asynchronous functions should use this in
order to provide a guarantee to their callers that cancelling an
async operation will reliably result in an error being returned for
that operation (even if a positive result for the operation has
already been sent as an idle to the main context to be dispatched).
Sets a #GCancellable to check before dispatching results.
This function has one very specific purpose: the provided cancellable is checked at the time of gio.simple_async_result.SimpleAsyncResult.propagateError If it is cancelled, these functions will return an "Operation was cancelled" error (gio.types.IOErrorEnum.Cancelled).
Implementors of cancellable asynchronous functions should use this in order to provide a guarantee to their callers that cancelling an async operation will reliably result in an error being returned for that operation (even if a positive result for the operation has already been sent as an idle to the main context to be dispatched).
The checking described above is done regardless of any call to the unrelated gio.simple_async_result.SimpleAsyncResult.setHandleCancellation function.