how do I poll with Rx? I want to keep querying an endpoint until its content include some value, and I want to be querying it 2 seconds apart for example until that result is found

I haven't actually used Rx productively in a while, but I would assume something like:

interval(2.seconds)
  .flatMap {
     // create observable that queries endpoint
   }
   .takeUntil {
     // it has expected content
   }

ahh interval

you can use filter - take1 or other variant