public double getHighWaterMarkPercent() {
      return highWaterMarkPercent;
    }
A thread-safe value object that represents a policy entry for disk quotas. When the percentage
of available disk space assigned via the disk quota drops below the low water mark the
configured work rate is applied to reduce throughput of the task. When the available disk space
rises above the high water mark the work rate throttling is removed (but other entries may
still apply).
samza-core/src/main/java/org/apache/samza/container/disk/WatermarkDiskQuotaPolicy.java