This is a non-breaking change proposal to extend refCount() with two optional parameters, attackTime and releaseTime.

refCount(attack?: number, release?: number)

The motivation: I have discovered a use case where I need a connectable observable to get connected, but not get disconnected/reconnected if the number of observers went from 1 to 0 then from 0 to 1 synchronously (in the same event loop). In the link above, I just used connect() without disconnecting it, which is bad for memory management. I can imagine other use cases where I'd like to delay the auto-disconnect implicit in the refCount.

For symmetry with release, I also included attack times in case that makes sense in some case.

From the Rx.NET gitter chat Lee Campbell also mentioned the existence of a LazyConnect operator they have which would be refCount(0, Infinity) ("connect when first observer subscribes, but never disconnect").

What do you think? This is definitely an advanced feature that most people don't need to use, but as a silent addition I think it's neat to avoid the imperative connect() whenever naive refCount() isn't enough.