code: private void initVariables() {
      mSumCapacityBytes = 0;
      mSumUsedBytes = 0;
      mSumCapacityBytesOnTierMap = new TreeMap<>(FileSystemAdminShellUtils::compareTierNames);
      mSumUsedBytesOnTierMap = new TreeMap<>(FileSystemAdminShellUtils::compareTierNames);
  
      // TierInfoMap is of form Map<Tier_Name, Map<Worker_Name, Worker_Tier_Value>>
      mCapacityTierInfoMap = new TreeMap<>(FileSystemAdminShellUtils::compareTierNames);
      mUsedTierInfoMap = new TreeMap<>(FileSystemAdminShellUtils::compareTierNames);
    }
docs: Initializes member variables used to collect worker info.