@Override
  protected void chore() {
    try {
      if (LOG.isTraceEnabled()) {
        LOG.trace("Computing sizes of snapshots for quota management.");
      }
      long start = System.nanoTime();
      _chore();
      if (null != metrics) {
        metrics.incrementSnapshotObserverTime((System.nanoTime() - start) / 1_000_000);
      }
    } catch (IOException e) {
      LOG.warn("Failed to compute the size of snapshots, will retry", e);
    }
  }
A Master-invoked {@code Chore} that computes the size of each snapshot which was created from a
table which has a space quota.
hbase-server/src/main/java/org/apache/hadoop/hbase/quotas/SnapshotQuotaObserverChore.java