[Haskell-cafe] typeclass for rest resource clients

Hi, for a project of mine I want to abstract away the rest resources (client side) and provide a stub implementation of the backend that I can use for testing. I thought about a StateT based stub instance, however one of the methods besides the usual crud stuff should be `waitFor` so that I can wait for resources to reach a certain state. Very concretely I want to create kubernetes pods and have my code wait until the pod is `Running`. What would I have to throw into the mix in order to have a stub that creates a pod and only later changes the status to `Running`? Any thoughts, advice or hint? Best Jan