default long getCurrentTimeInMillis() {
        return getCurrentWallClockTime().toEpochMilli();
    }
Interface used to get time. This is separated into its own class, such that unit tests can fake timing to do timing related
tests without relying on the speed of the unit test processing.
clustercontroller-core/src/main/java/com/yahoo/vespa/clustercontroller/core/Timer.java