Observable.map unsubscribe question #4242

Just looking at OnSubscribeMap and I noticed a possibly undesirable unsubscribe() call in MapSubscriber (L72):

        @Override
        public void onNext(T t) {
            R result;

            try {
                result = mapper.call(t);
            } catch (Throwable ex) {
                Exceptions.throwIfFatal(ex);
                unsubscribe();
                onError(OnErrorThrowable.addValueAsLastCause(ex, t));
                return;
            }

            actual.onNext(result);
        }

If an exception occurs we eagerly unsubscribe from the source before emitting the error. I'm not sure we have a policy on this yet but my first impression is that a length unsubscribe activity could delay the emission of the error and this might not be expected. I wonder if we should delete this unsubscribe() call?