InformerManager and FederatedInformerManager manage informers for the host and member clusters, respectively, based on FederatedTypeConfigs. For each FederatedTypeConfig, the managers start an informer for the corresponding type.

If the informer for a type cannot be started or its cache cannot be synced (be it for host cluster or member clusters), we should expose this information for visibility. The current mechanism for doing so is by including the information in the response returned by the controller manager's readyz endpoint. Refer to existing controller's readyz implementation for how one can implement cache sync check for InformerManager and FederaterdInformerManager.