using<T, R> static method
When listener listens to it, creates a resource object from resource factory function,
and creates a Single from the given factory function and resource as argument.
Finally when the Single finishes emitting items or stream subscription
is cancelled (call StreamSubscription.cancel or Single.listen(cancelOnError: true)),
call the disposer function on resource object.
This method is a way you can instruct a Single to create a resource that exists only during the lifespan of the Single and is disposed of when the Single terminates.
The returned Single is single-subscription Stream.
Example
class Resource {
void close() => print('Closed');
int get value => 0;
}
RxSingles.using<int, Resource>(
() => Resource(),
(r) => Single.value(r.value),
(r) => r.close(),
).listen(print); // prints 0, Closed
See Rx.using and UsingStream.
Implementation
static Single<T> using<T, R>(
R Function() resourceFactory,
Single<T> Function(R) singleFactory,
FutureOr<void> Function(R) disposer,
) =>
Single.safe(
Rx.using(
resourceFactory,
singleFactory,
disposer,
),
);