void initializeSnapshotStores(Map<RegionInfo, Long> regionSizes) {
    Map<RegionInfo, Long> immutableRegionSpaceUse = Collections.unmodifiableMap(regionSizes);
    if (tableSnapshotStore == null) {
      tableSnapshotStore = new TableQuotaSnapshotStore(conn, this, immutableRegionSpaceUse);
    } else {
      tableSnapshotStore.setRegionUsage(immutableRegionSpaceUse);
    }
    if (namespaceSnapshotStore == null) {
      namespaceSnapshotStore = new NamespaceQuotaSnapshotStore(conn, this, immutableRegionSpaceUse);
    } else {
      namespaceSnapshotStore.setRegionUsage(immutableRegionSpaceUse);
    }
  }
Reads the currently received Region filesystem-space use reports and acts on those which violate
a defined quota.
hbase-server/src/main/java/org/apache/hadoop/hbase/quotas/QuotaObserverChore.java