private SpaceQuotaSnapshot getSnapshotForTable(Connection conn, TableName tn) throws IOException {
    try (Table quotaTable = conn.getTable(QuotaUtil.QUOTA_TABLE_NAME);
      ResultScanner scanner = quotaTable.getScanner(QuotaTableUtil.makeQuotaSnapshotScan())) {
      Map<TableName, SpaceQuotaSnapshot> activeViolations = new HashMap<>();
      for (Result result : scanner) {
        try {
          QuotaTableUtil.extractQuotaSnapshot(result, activeViolations);
        } catch (IllegalArgumentException e) {
          final String msg = "Failed to parse result for row " + Bytes.toString(result.getRow());
          LOG.error(msg, e);
          throw new IOException(msg, e);
        }
      }
      return activeViolations.get(tn);
    }
  }
A test case to verify that region reports are expired when they are not sent.
hbase-server/src/test/java/org/apache/hadoop/hbase/quotas/TestQuotaObserverChoreRegionReports.java