maybe
fun <T, R> maybeUsing(resourceSupplier: () -> R, resourceCleanup: (resource: R) -> Unit, eager: Boolean = true, sourceSupplier: (resource: R) -> Maybe<T>): Maybe<T>
Returns a Maybe that for each subscription acquires a new resource via resourceSupplier, then calls sourceSupplier and subscribes to the returned upstream Maybe and disposes the resource via sourceSupplier when the upstream Maybe is finished (either terminated or disposed).
Please refer to the corresponding RxJava document.