@JsonAnySetter
  public void add(String partitionClassName, Map<Short, Map<Short, ContainerStorageStats>> allAccountStats) {
    storageStats.put(partitionClassName, allAccountStats);
  }
Add partition class name and partition class storage stats in this {@link AggregatedPartitionClassStorageStats}.
@param partitionClassName The partition class name.
@param allAccountStats The partition class level (all accounts in this partition class) stats.
ambry-api/src/main/java/com/github/ambry/server/storagestats/AggregatedPartitionClassStorageStats.java