// The 'usable' lock is always 'RLock'able when it is safe to use the cache.
	// It is safe to use the cache after a successful list until a disconnection.
	// We start with usable (write) locked. The below OnReplace function will
	// unlock it after a successful list. The below defer will then re-lock
	// it when this function exits (always due to disconnection), only if