src/main/java/io/reactivex/disposables/Disposables.java
@NonNull
    public static Disposable fromSubscription(@NonNull Subscription subscription) {
        ObjectHelper.requireNonNull(subscription, "subscription is null");
        return new SubscriptionDisposable(subscription);
    }
@NonNull
    public static Disposable fromSubscription(@NonNull Subscription subscription) {
        ObjectHelper.requireNonNull(subscription, "subscription is null");
        return new SubscriptionDisposable(subscription);
    }
Construct a Disposable by wrapping a Subscription that is
cancelled exactly once when the Disposable is disposed.
@param subscription the Runnable to wrap
@return the new Disposable instance