docs: @NotNull public static Completable from(@NotNull final ApolloPrefetch prefetch) {
      checkNotNull(prefetch, "prefetch == null");
      return Completable.create(new Completable.OnSubscribe() {
        @Override public void call(final CompletableSubscriber subscriber) {
          final Subscription subscription = getSubscription(subscriber, prefetch);
          prefetch.enqueue(new ApolloPrefetch.Callback() {
            @Override public void onSuccess() {
              if (!subscription.isUnsubscribed()) {
                subscriber.onCompleted();
              }
            }
  
            @Override public void onFailure(@NotNull ApolloException e) {
              Exceptions.throwIfFatal(e);
              if (!subscription.isUnsubscribed()) {
                subscriber.onError(e);
              }
            }
          });
        }
      });
    }