static JvmMemoryPercentage of(int percentageOfAvailable, int percentageOfTotal, double absoluteMemoryGb) {
            return new JvmMemoryPercentage(percentageOfAvailable, OptionalInt.of(percentageOfTotal), OptionalDouble.of(absoluteMemoryGb));
        }
Returns the percentage of host physical memory this application has specified for nodes in this cluster,
or empty if this is not specified by the application.
config-model/src/main/java/com/yahoo/vespa/model/container/ContainerCluster.java