Possible memory leak with Eventuals #118
Description
Eventuals are great but they are a simpler and less used version of RxJs.
It's been known by a long time that indexer-service (ts version) and indexer-agent have a memory leak that grows constantly no matter how many subgraphs are being served.
The only thing that runs constantly on a time based and is shared between those components are eventuals.
I propose updating the implementation of Eventuals to use RxJs because it's widely used and well tested.