Potentially unused property "observerSlots" in internal implementation of Solid

[NesCafe62]

I noticed that observerSlots property that is set in readSignal function only used for read it one place - in cleanNode, but how it is used - it is just saved to another index
https://github.com/solidjs/solid/blob/main/packages/solid/src/reactive/signal.ts#L1276 (set observerSlots, also line:1279)
https://github.com/solidjs/solid/blob/main/packages/solid/src/reactive/signal.ts#L1630 (read of observerSlots)

I'm working on own reactivity library and first used same approach as I saw in Solid (to store dependencies between reactive atoms) with 4 arrays: observers, observerSlots, sources, sourceSlots. when I noticed that I don't use observerSlots I removed it and saw that reactivity in my library still works!

marked with green line:1630 where it's read, line:1634 is where it is written. but there is no other reads

note: this property might be still useful if we would need to remove all observers (not all sources which is what cleanNode does) or to remove specific observer