private void checkQuotaSupport() throws IOException {
    if (!QuotaUtil.isQuotaEnabled(masterServices.getConfiguration())) {
      throw new DoNotRetryIOException(new UnsupportedOperationException("quota support disabled"));
    }
    if (!initialized) {
      long maxWaitTime = masterServices.getConfiguration()
        .getLong("hbase.master.wait.for.quota.manager.init", 30000); // default is 30 seconds.
      long startTime = EnvironmentEdgeManager.currentTime();
      do {
        try {
          Thread.sleep(100);
        } catch (InterruptedException e) {
          LOG.warn("Interrupted while waiting for Quota Manager to be initialized.");
          break;
        }
      } while (!initialized && (EnvironmentEdgeManager.currentTime() - startTime) < maxWaitTime);
      if (!initialized) {
        throw new IOException("Quota manager is uninitialized, please retry later.");
      }
    }
  }
Performs some action after {@link #update(GlobalQuotaSettingsImpl)} with the resulting quota
from the request action for the subject.
hbase-server/src/main/java/org/apache/hadoop/hbase/quotas/MasterQuotaManager.java