boolean updateAccounts(Collection<Account> accounts) {
    ZKUpdater zkUpdater = createNewZKUpdater(accounts);
    boolean hasSucceeded = helixStore.update(znRecordPath, zkUpdater, AccessOption.PERSISTENT);
    zkUpdater.afterUpdate(hasSucceeded);
    return hasSucceeded;
  }
updateAccounts updates the latest full set of {@link Account} metadata and save it in the storage.
@param accounts The {@link Account} collection to update. It will not be null or empty.
@return false when there is any error.
ambry-account/src/main/java/com/github/ambry/account/AccountMetadataStore.java