void setNamespaceQuotaSnapshot(String namespace, SpaceQuotaSnapshot snapshot) {
    this.namespaceQuotaSnapshots.put(namespace, snapshot);
  }
Stores the given {@code snapshot} for the given {@code namespace} in this chore.
hbase-server/src/main/java/org/apache/hadoop/hbase/quotas/QuotaObserverChore.java